Question : Printing from .NET Windows Service - Object reference not set to an instance of an object

I am modifying a .NET Windows Service in VS .NET 2003 on Windows XP that sweeps a database for address data and prints a PDF letter from a template.  I am getting the error, "Object reference not set to an instance of an object" from the function that prints the PDF letter.  The code is shown below.  The error is being generated from the AddToEventLog after the Catch.  Would appreciate any help yall can provide.  I am a newbie at .NET programming and did not actually write this service but have been assigned to modify it.  It currently works in production on a Windows 2000 machine.

Thanks in advance
Annie

    Private Sub printPDFFile(ByVal strOutputFile As String)
        Dim objStartInfo As New ProcessStartInfo
        Dim objProcess As New System.Diagnostics.Process

        If IsValidPrinter() Then
            ' set start info properties
            With objStartInfo
                .CreateNoWindow = True
                .FileName = AcrobatReaderExecutable
                .Arguments = "/t " & strOutputFile & " " & ServicePrinterName
                .UseShellExecute = True
                .WindowStyle = ProcessWindowStyle.Hidden
                .ErrorDialog = True
                '.RedirectStandardError = True
            End With

            ' start process
            Try
                objProcess = Process.Start(objStartInfo)
                objProcess.Close()

               ' print to event log
                AddToEventLog("Attempting to print generated " & getWordString() & " letter '" & strOutputFile & "' to printer [" & ServicePrinterName & "]", EventLogEntryType.Information)
            Catch ex As Exception
                ' error occurred
                AddToEventLog("Error encountered while attempting to print PDF file to printer [" & ServicePrinterName & "] " & vbCrLf & ex.Message & vbCrLf & ex.Source & vbCrLf & ex.TargetSite.Name, EventLogEntryType.Error)
            End Try
        Else
            ' printer not valid
            AddToEventLog("The file '" & strOutputFile & "' cannot be printed.  The printer [" & ServicePrinterName & "] either is not valid or has not been setup as a printer on this machine.", EventLogEntryType.Error)
        End If

    End Sub

Answer : Printing from .NET Windows Service - Object reference not set to an instance of an object

Just to clarify:  You don't necessarily want to shut it down if it's already running because presumably it's running for a reason.  The code I posted above will only shut the process down if it was started by your code.