Problem deleting a file (being used by another process)??

Hi,

I have a windows service app that uses a filesystemwatcher.  When a file gets created in a particular directory that I am watching it checks whether the file needs to be processed (by a db check).  If there is no actions to be taken,  the file gets deleted.

I have been pasting the file into the directory to check that it works.  When I attach to the process and debug everything works fine and the file gets deleted every time.  Which is what I want.  However when I am not debugging the file gets deleted the first time but when I paste the file in again I get the following error:

System.io.IOException - {"The process cannot access the file 'C:\test\test1.asf' because it is being used by another process."}

Any ideas why this is happening?  Here is my code:

Private Sub ActionFile(ByVal source As Object, ByVal e As System.IO.FileSystemEventArgs)
        If e.ChangeType = WatcherChangeTypes.Created Then
            'If a new file has been created then action the file by moving it to the correct directory
            'Check that the file is an asf file
            If e.Name.Contains(".asf") Then

                'Get the directory structure for the new file so that we can move it to the correct place
                Dim strDir As String = GetDirStructure("test")
                If strDir <> "" Then

                    If Not Directory.Exists(strDir) Then
                        Directory.CreateDirectory(strDir)
                    End If

                    File.Move(e.FullPath, strDir & "\" & e.Name)
                Else 'A directory for this file has not been created so delete the capture
                    File.Delete(e.FullPath)

                End If

            End If

        End If
    End Sub