[MonoDevelop] nunit Problem in MonoDevelop 2.6

[Jim Orcheson]

I created a solution that included a set of nunit tests on Ubuntu 11.04 
(MonoDevelop 2.4.X, mono 2.6.7, and some version of nunit). There were 
no problems.

When I upgraded to Ubuntu 11.10, (MonoDevelop 2.6, mono 2.10.5, and 
nunit 2.5.10) I had the usual teething problems but eventually got 
everything to build. However, when I attempt to run any of the unit 
tests, I get the following in MonoDevelop:

Test Results for MyTests configuration Debug|x86
Internal Error
     NullReferenceException: Object reference not set to an instance of 
an object
     Stack Trace
         at 
System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(System.Runtime.Proxies.RealProxy 
rp,
                     IMessage msg, System.Exception& &exc, 
System.Object[]& out_args) [0x00000] in
<filename unknown>:0

This message is so useful (not) that I have no idea where to even start 
determining what has gone wrong. Can anybody point me to what is missing?

Thanks,

Jim