Clear out multicast listeners in .NET

I have a problem where sometimes when I call UdpClient.JoinMulticastGroup (.NET call), I get a "system lacked sufficient buffer space or because a queue was full" exception (details here).

Is there some SDK call where I can have it close all orphan multi-cast listeners? Or close all on a given addres开发者_如何学JAVAs/port?

I think I know the cause - it occurs when our program which has a worker thread listening on the multicast port is killed a couple of times in the debugger. If I do that enough, I then get this.

My question is how can I tell it to drop resources for apps that are dead? My app is a .NET Word AddIn.

thanks - dave