Debugger problem

All of a sudden I have the following problem when I debug a MCMS application
:

I put a breakpoint on a line which contains a MCMS object.
The debugger stops at the line with the MCMS object.
When I right-click and do a QuickWatch on the MCMS object, I always get the
following error: "Run-time exception thrown : System.ArgumentException -
Cannot find the method on the object instance."

This makes for difficult debugging.  What is wrong?  I know it's not a MCMS
problem because the web application runs fine.  It's debuggin that is a PITA
.

TIA,
Adam