SHFileOperation Anomaly

I create the code below for simplify copy across drives. It's ok if I run the program from harddisk, but when I burn it to CD-ROM or run this copy program from Diskette, it said "cannot copy file: file system error (1026)".

procedure FileOperation(Handle: HWND;
                        SourcePath, TargetPath: string;
                        Operation: byte);
var
  opInfo : _SHFILEOPSTRUCT;

begin
  opInfo.pFrom := PChar(SourcePath);  //SourceFolder
  opInfo.pTo   := PChar(TargetPath);  //DestinationFolder
  case Operation of
  1: begin
       opInfo.wFunc := FO_MOVE;
       opInfo.lpszProgressTitle := 'Moving . . .';
     end;
  2: begin
       opInfo.wFunc := FO_COPY;
       opInfo.lpszProgressTitle := 'Copying . . .';
     end;
  3: begin
       opInfo.wFunc := FO_DELETE;
       opInfo.lpszProgressTitle := 'Deleting . . .';
     end;
  4: begin
       opInfo.wFunc := FO_RENAME;
       opInfo.lpszProgressTitle := 'Renaming . . .';
     end;
  end;
  opInfo.fFlags := FOF_NOCONFIRMATION  or //no confirmation
                   FOF_NOCONFIRMMKDIR or  //no confirmation
                   FOF_FILESONLY or //Only files effected and must use wildcard *.*
                   FOF_SIMPLEPROGRESS;  //show a progress
  opInfo.hNameMappings := nil;  // no mappings
  opInfo.fAnyOperationsAborted := False; //obsolete
  opInfo.Wnd := Handle;  //the parent of the progressdisplay
  SHFileOperation(opInfo);
end;

The strange also happen when I simply add this code simply to show wether the sourcepath and targetpath is ok :

ShowMessage('source='+SourcePath+' target='+TargetPath);

It cause the same 1026 error even I run the program from harddisk and copy from diskette a:\*.* to a folder in harddisk c:\test\

also the other strange thing is when I do this program from CD-ROM and got error 1026 and do it again, it run ok, it copy files from folder in my CD-ROM to a folder on my harddisk.

Can experts help me fix this ?