Error in saving TIFF in CCITT4 compression format

The Function is able to Compress Image in CompressionLZW compressin format. If I change the compression type to CompressionCCITT4, it gives me "An unhandled exception of type 'System.ArgumentException' occurred in system.drawing.dll Additional information: Invalid parameter used." exception while saving the image. I am using .NET framework 1.1.

//This function will do the Image Compression.
            //Input Parameter - Tif Image Path
            //Output Parameter - Compressed Tif Image.      
public int  CompressTiffImage(string strImagePath ,ref string strOutPath,ref string strMessage)
            {
                  try
                  {
                        //Place Holders...
                        int  iIndxTiffName = strImagePath.LastIndexOf("\\");
                        string strTiffName = strImagePath.Substring(iIndxTiffName+1);
                        int iTiffLength =strTiffName.Length;
                        string strPath = strImagePath.Remove(iIndxTiffName +1,iTiffLength);
                        string sOutPath  = "";                        
                        int iframe = 0;      
                        
                        //Encoders.                  
                        Encoder enc = Encoder.Compression;                        
                        
                        //EncodeParameters.
                        EncoderParameters ep=new EncoderParameters(1);
                        ep = new EncoderParameters(1);                        
                        //ep.Param[0]=new EncoderParameter(enc,(long)EncoderValue.CompressionNone);
                        ep.Param[0] = new EncoderParameter(Encoder.Compression,(long)EncoderValue.CompressionCCITT4);                         
                        string temp="image/tiff";                        
                        ImageCodecInfo info=GetEncoderInfo(ref temp);//Set image type to tiff
                        
                        //create the Temp Tiff Directory
                        DirectoryInfo di = Directory.CreateDirectory(strPath + "tifs\\");
                        
                        //Splitting the Images...                                                
                        Image pages= (Bitmap) Image.FromFile(strImagePath);      
                        FrameDimension oDimension = new FrameDimension(pages.FrameDimensionsList[0]);
                        int FrameCount = pages.GetFrameCount(oDimension);                                                            
                        ArrayList TiffFiles = new ArrayList();                        
                        for(int frame = 0; frame< FrameCount; frame++)
                        {                                    
                              pages.SelectActiveFrame(oDimension,frame);            
                              string sPixelF = pages.PixelFormat.ToString();                                    
                              //pages.Save(strPath + "tifs\\" + strTiffName+frame + ".tiff",info,ep);
                              pages.Save(strPath + "tifs\\" + strTiffName+frame + ".tiff",ImageFormat.Tiff);
                              TiffFiles.Add(strPath + "tifs\\" + strTiffName+frame + ".tiff");
                        }                                          
                        int iRet = AppendSplittedTiffImages(TiffFiles,ref iframe,ref sOutPath,ref strMessage);            
                        //delete the Object.
                        pages.Dispose();
                        //delete the original file
                        File.Delete(strImagePath);                        
                        //copy the compressed.
                        File.Copy(sOutPath,strImagePath);
                        //Delete the directory.
                        di.Delete(true);
                        //return the compressed file.
                        strOutPath = strImagePath;      
                        if (iRet != 0)
                        {                              
                              return 1;
                        }            
                  }
                  catch (Exception ex)
                  {
                        strOutPath = null;
                        strMessage = ex.ToString();
                        Console.Write(strMessage);
                        EventLog.WriteEntry(API_NAME,strMessage,EventLogEntryType.Error);  
                        return 1;
                  }                  
                  return 0;
            }


      private int  AppendSplittedTiffImages(ArrayList imageFiles,ref int frame ,ref string strOutPath,ref string strMessage)
            {
                  try
                  {
                        //Place Holders...
                        bool bDirExists = false;
                        string sDirPath;
                        string sImageFile;
                        //use the save encoder
                        Encoder enc=Encoder.SaveFlag;
                        EncoderParameters ep=new EncoderParameters(2);
                        ep.Param[0]=new EncoderParameter(enc,(long)EncoderValue.MultiFrame);
                        ep.Param[1] = new EncoderParameter(Encoder.Compression ,(long)EncoderValue.CompressionLZW);

                        Bitmap pages=null;
                        frame=0;      //Set the frame count to zero
                        string temp="image/tiff";
                        ImageCodecInfo info=GetEncoderInfo(ref temp);//Set image type to tiff
                              

                        //EventLog.WriteEntry(API_NAME,strMessage,EventLogEntryType.Information);
                        //For each image, append the bitmap for each image to the last image saved
                        foreach(string strImageFile in imageFiles)
                        {
                              int IndexOfSlash = strImageFile.LastIndexOf("\\");
                              sImageFile = strImageFile.Substring(IndexOfSlash +1);
                              int strImageFileLength = sImageFile.Length;
                              string Path= strImageFile.Remove(IndexOfSlash +1,strImageFileLength);
                              string sNewPath = Path.Substring(0,Path.Length -1);
                              int sDirIndx = sNewPath.LastIndexOf("\\");
                              string sDirName = sNewPath.Substring(sDirIndx + 1);
                              sDirPath = Path+sDirName;
                              
                              //check  the directory exists or not
                              bDirExists = Directory.Exists(sDirPath);
                              if (!bDirExists)
                              {
                                    DirectoryInfo di = Directory.CreateDirectory(sDirPath);
                              }      
                              if(frame==0)
                              {                                          
                                    //strOutPath = sDirPath + sImageFile;
                                    pages=(Bitmap)Image.FromFile(Path +sImageFile);
                                    //save the first frame
                                    pages.Save(sDirPath + "\\"+ sImageFile,info,ep);
                                    //Store the final Appended Image Path for Returning.
                                    strOutPath = sDirPath + "\\"+ sImageFile;                                          
                              }
                              else
                              {
                                    //save the intermediate frames
                                    ep.Param[0]=new EncoderParameter(enc,(long)EncoderValue.FrameDimensionPage);
                                    Bitmap bm=(Bitmap)Image.FromFile(Path + sImageFile);
                                    pages.SaveAdd(bm,ep);
                                    bm.Dispose();                                    
                              }      
                              if(frame==imageFiles.Count -1)
                              {
                                    //flush and close.
                                    ep.Param[0]=new EncoderParameter(enc,(long)EncoderValue.Flush);
                                    pages.SaveAdd(ep); //Save All the frames when the last image is encountered                              }
                              }
                              frame++;
                              
                        }
                        //return the final Image Path.
                        strMessage = "< "+ frame.ToString() + " >Images Appended Successfully";
                        //Clean up
                        pages.Dispose();
                        ep.Dispose();      
                        foreach(string strImageFile in imageFiles)
                        {                              
                              File.Delete(strImageFile);
                        }                        
                  }
                  catch (Exception ex)
                  {
                        strOutPath = null;
                        strMessage = ex.ToString();
                        EventLog.WriteEntry(API_NAME,strMessage,EventLogEntryType.Error);  
                        Console.WriteLine(strMessage);
                        return 1;
                  }
                  
                  return 0;
            }            

            
            //Get EncoderInfo - For the Mime Type      
            private ImageCodecInfo GetEncoderInfo(ref string mimeType)
            {
                  ImageCodecInfo[] encoders=ImageCodecInfo.GetImageEncoders();
                  for (int j=0;j<encoders.Length;j++)
                  {
                        if (encoders[j].MimeType==mimeType)
                              return encoders[j];
                  }
                  
                  throw new Exception( mimeType + " mime type not found in ImageCodecInfo" );
            }