Uploading File to Sharepoint 2010 using PS

Ok, I'm a novice to both Sharepoint and Powershell.  Have looked up many ways to script uploading a file to Sharepoint.  So here's where I am now stuck.  Here is the script:


if((Get-PSSnapin "Microsoft.SharePoint.PowerShell") -eq $null)
{
    Add-PSSnapin Microsoft.SharePoint.PowerShell
}
 
#Script settings
 
#SiteName
$webUrl = "http://sharepointserver" 
 
#SharePoint Library Name
$SPLibraryName = "Documents"
 
#library URL  
$SPLibraryUrl = "http://sharepointserver/sites/ost/documents" 
 
#Location where from you want to upload file to SharePoint lib.
$localFolderPath = "C:\Dockets"
 
 
 
#Open web and library
 #Site URL
$web = Get-SPWeb $webUrl
 #Libray Name
$docLibrary = $web.Lists[$SPLibraryName]
 
 #Getting All Files
 $files = ([System.IO.DirectoryInfo] (Get-Item $localFolderPath)).GetFiles()
 
ForEach($file in $files)
{
 
    #Open file
    $fileStream = ([System.IO.FileInfo] (Get-Item $file.FullName)).OpenRead()
 
    #Add file
    $folder =  $web.getfolder($SPLibraryUrl)
 
    write-host "Copying file " $file.Name " to " $folder.ServerRelativeUrl "..."
    $spFile = $folder.Files.Add($folder.Url + "/" + $file.Name, [System.IO.Stream]$fileStream, $true)
    write-host "Success"
 
    #Close file stream
    $fileStream.Close();
}
 
#Dispose web
 
$web.Dispose()

Here is the error I get:  

Exception calling "Add" with "3" argument(s): "<nativehr>0x80070003</nativehr><nativestack></nativestack>There is no file with URL 'http://sharepointserver/sites/ost/documents/<filename>,pdf' in this
Web."
At C:\Scripts\CopyFilesSP.ps1:41 char:32
+     $spFile = $folder.Files.Add <<<< ($folder.Url + "/" + $file.Name, [System.IO.Stream]$fileStream, $true)
    + CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
    + FullyQualifiedErrorId : DotNetMethodException