"Cannot get value"errors for $FILE,$Signature

[D G]

I am getting the following exceptions every time I encounter either the $FILE or $Signature field (see below).

I am using Domingo 1.5.1 and Notes.jar from the Domino 8.0 installation. Has something changed in 8.0 that Domingo is not being compatible with?

Caused by: de.bea.domingo.service.NotesServiceException: NotesServiceFactory.invoke() <init>
      at de.bea.domingo.service.NotesServiceFactory.invoke(NotesServiceFactory.java:386)
      at de.bea.domingo.service.NotesInvocationHandler.invoke(NotesInvocationHandler.java:87)
      ... 11 more
Caused by: java.lang.NoSuchMethodError: <init>
      at lotus.domino.local.Document.NgetItemValueDateTimeArray(Native Method)
      at lotus.domino.local.Document.getItemValueDateTimeArray(Unknown Source)
      at de.bea.domingo.proxy.BaseDocumentProxy.getItemValue(BaseDocumentProxy.java:413)
      at sun.reflect.GeneratedMethodAccessor5.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:597)
      at de.bea.domingo.service.InvocationTask.run(InvocationTask.java:102)
      at de.bea.domingo.threadpool.SimpleThreadPool.run(SimpleThreadPool.java:369)
      at de.bea.domingo.proxy.DNotesThread.run(DNotesThread.java:244)
de.bea.domingo.service.NotesServiceRuntimeException: de.bea.domingo.proxy.DocumentProxy: Cannot get value of item $FILE
      at de.bea.domingo.service.NotesServiceFactory.invoke(NotesServiceFactory.java:382)
      at de.bea.domingo.service.NotesInvocationHandler.invoke(NotesInvocationHandler.java:87)
      at $Proxy3.getItemValue(Unknown Source)