I believe you can use the FileInfo.OpenWrite() method to check if the file is avaialbe for opening to write (assuming that you will not be able to if something else is writing to it)

Dim oLoadFile As FileInfo = New FileInfo(cFilePath)

Dim lComplete As Boolean

Complete = False

...

'Loop until the file is openable (e.g. FTP or copy complete) or iTimeOut is reached

While lComplete = False

lComplete = True

Try

oLoadFile.OpenWrite()

Catch

lComplete = False

System.Threading.Thread.Sleep(iCycleTime)

End If

i += iCycleTime

If i > iTimeOut Then

Exit While

End Try

End While

...etc