referencing a dll in a windows service - vb.net

Question

I wrote an OPC client using interop.opcautomation.dll. I wrote it as a windows form in vb 2010 express. everything is currently working well. I wanted to make it a windows service though. The problem I am having is that it will not connect to the opc server when I run the service. I get the following exception "Object reference not set to an instance of an object.- OPC Connect Error" I get the exception at the end of the code where I am trying to connect. Below is the code. Thanks for any input, it is appreciated.
Imports System.ServiceProcess
Imports System.Threading
Imports System.Text
Imports System.Windows.Forms
Imports System
Imports System.IO
Imports System.IO.File
Imports System.Net
Imports OPCAutomation
Public Class Service1
Inherits System.ServiceProcess.ServiceBase
Dim WithEvents OPCServer As OPCAutomation.OPCServer
Dim WithEvents ConnectedGroup As OPCAutomation.OPCGroup
Dim Batch As String
Dim Group As String
Dim Press As String
Dim Line As String
Dim sWidth As String
Dim sHeight As String
Dim sBifold As String
Dim sCore As String
Dim StartUp As Integer
Dim iHandle As Integer
Dim sError As String
Dim ItemIds(60) As String
Dim ServerHandles As Array
Dim ClientHandles(60) As Integer
Dim ServerErrors As Array
Dim SnapServerURL As String = "snapserver"
Private trd As Thread
Private Stopping As Boolean = False
Private StoppedEvent As New ManualResetEvent(False)
Protected Overrides Sub OnStart(ByVal args() As String)
EventLog.WriteEntry("PressControlService in OnStart.")
trd = New Thread(AddressOf ServiceMain)
trd.IsBackground = True
trd.Start()
End Sub
Protected Overrides Sub OnStop()
EventLog.WriteEntry("PressControlService in OnStop.")
Me.Stopping = True
Me.StoppedEvent.WaitOne()
End Sub
Private Sub ServiceMain()
Dim strOPCServerName As String
Dim strOPCServerNode As String
Dim strOPCGroupName As String
Dim i As Integer
StartUp = 0
strOPCServerName = "Kepware.KEPServerEX.V5"
strOPCServerNode = ""
strOPCGroupName = "MyGroup"
Try
Dim OPCServer As New OPCAutomation.OPCServer
Catch ex As Exception
EventLog.WriteEntry(ex.Message & " - New OPC Server")
End Try
Try
OPCServer.Connect(strOPCServerName, strOPCServerNode)
Catch ex As Exception
EventLog.WriteEntry(ex.Message & "- OPC Connect Error")
End Try
End Sub
End Class