OpcNetApi Group Subscription DataChangedEventHandler throws System.NullReferenceException|Classic OPC: DA, A&E, HDA, XML-DA, etc.|Forum|OPC Foundation

I have a basic subscription and it works fine on my development computer. But for the life of me I am unable to deploy it to a server. When I run the application it throws an error on this specific line of code (highlighted in red):

Note: I have OPC Core Components Redistributable x64 3.0.107.24 installed.

groupState = new Opc.Da.SubscriptionState();

groupState.Name = "Group";

groupState.Active = true;

group = (Opc.Da.Subscription)opcServer.CreateSubscription(groupState);

group.DataChanged += new Opc.Da.DataChangedEventHandler(OnTransactionCompleted);

I get a System.NullReferenceException: Object reference not set to an instance of an object.

I will get a COMException during runtime.

System.Runtime.InteropServices.COMException (0x80040202): Exception from HRESULT: 0x80040202.
   at OpcRcw.Comn.IConnectionPoint.Advise(Object pUnkSink, Int32& pdwCookie)
   at OpcCom.ConnectionPoint.Advise(Object callback)
   at OpcCom.Da.Subscription.Advise()
   at OpcCom.Da.Subscription.add_DataChanged(DataChangedEventHandler value)
   at Opc.Da.Subscription.add_DataChanged(DataChangedEventHandler value)
   at BackFlush_POC.myOPC.connectOPC()

The same exact .exe run on my dev computer works with no issues.

Has anyone seen something like this? I've been struggling with this for days. Thanks.