Undo Operation Encountered Exception

I have created an application using asynchronous sockets that starts a local server, allows clients to connect to it. When the server starts, it creates an inherited version of my client class to create a connection to a unix server. There is no real difference in the connection, only the way data is handled when it comes back. When the server starts, the unix client creates a connection through to the remote point, sends a message and receives a response. This works fine. When my windows based client connects to the server, it sends a message on connect as well, the server receives this and then forwards a message to the unix client to tell it to forward a wakeup to the unix system. On receipt of the message back from unix acknowledging this, the server crashes with the following message.

System.InvalidOperationException was unhandled
Message="The Undo operation encountered a context that is different from what was applied in the corresponding Set operation. The possible cause is that a context was Set on the thread and not reverted(undone)."
Source="mscorlib"
StackTrace:
at System.Threading.SynchronizationContextSwitcher.Undo()
at System.Threading.ExecutionContextSwitcher.Undo()
at System.Threading.ExecutionContext.runFinallyCode(Object userData, Boolean exceptionThrown)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteBackoutCodeHelper(Object backoutCode, Object userData, Boolean exceptionThrown)
at System.Runtime.CompilerServices.RuntimeHelpers.ExecuteCodeWithGuaranteedCleanup(TryCode code, CleanupCode backoutCode, Object userData)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Net.ContextAwareResult.Complete(IntPtr userToken)
at System.Net.LazyAsyncResult.ProtectedInvokeCallback(Object result, IntPtr userToken)
at System.Net.Sockets.BaseOverlappedAsyncResult.CompletionPortCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* nativeOverlapped)
at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32 errorCode, UInt32 numBytes, NativeOverlapped* pOVERLAP)

There is no indication of whereabouts in the program this happens, and the only other references to this problem I can find (forums.microsoft.com/msdn) have either no solution, or the solution makes no sense within my application.

In my send method, I set a waiting state, and within that loop I have an event in which I have Application.DoEvents( ) (I found it hangs otherwise and won't output anything until things have finished) removing that doesn't fix things. And any interaction I am having with the GUI at all I have wrapped in invoke (i only output log data to a richtext box). I'm at a loss as to how to proceed with this problem, and I don't know what I can change to fix it!

Any help appreciated.