threads freezing - help!

I have two additional threads running in my app.
Both are in a while loop.

In the loop, they are calling Snychronize to call a method of an
object also used in the main thread.

After a while, the main thread freezes (won't respond to mouse, etc.)
yet if I "pause" the program, I can see the other threads still

The problem is that when I step through the threads they are executing
code that the main thread should!!! How did the threads get confused
with their assignments?  What would I have done to cause this to

It seems to start when I load a particular form, so I'm sure the
problem lies therein.  I thought y'all might know offhand what would
cause this sort of anomaly.

Thanks in advance,