sure... add a call tyo DebugBreak() and select "debug" when you'll get the error message.... when youre in the VC deubbuger, looking at your code, just say to ignore the assertion and youre good to go.
The second sollution is to do something like
while(true)
Sleep(100); <-- put a breakpoint here
When execution comes to this point, it will freeze.. attach your debugger to the messenger process, you'll break at the Sleep line.. then, just set the next execution point below the Sleep line.
Pick whatever sollution you prefer
Patchou