CruiseControl.Net with MsBuild is giving me some strange behavior.

I've used CCNet in previous projects with nAnt to launch the build and I can't remember having any issues like the ones I have now.
It worked very smoothly.

In the project I am in now:
 -I use the msbuild and the msbuil task instead of nAnt.
 -The task is configured to use the the ThoughtWorks..XmlLogger. 
 -The build server running CC is a 64bit VMWare system.

I'm experiencing some reliability issues with this; frequent "Failure" and "Exception" results from builds. Sometimes a Force Build will fix the issue, but usually I need to restart the CCNet service. Sometimes I even need to reboot the CC server.

The most common "Exception" I've seen is an "attempt to read or write protected memory".
Other times, the status is just "Failure" and looking at the build log shows what seems to be a successful build :S

I'm not sure what to suspect as the source of the problem.
Is there anyone else using this same combination (on a virtual x64)?

If I could find a forum dedicated to CCNet, I'd post there...

Thanks for any suggestions about how to figure this out.

-Andrew