Visual Studio Express

I had been making good progress on project Unison, getting about three-fourths of the messages out of the game successfully. I had noticed a particular one fairly early, but decided to delay tackling it until later because it looked to be a symptom of other, smaller bugs. Finally, I had to tackle this bug; for some reason, a message would completely stop in the middle, but only after several messages had been sent in quick succession, and it would fix itself a few messages later. It's probably something to do with a loop condition or data integrity check; however, I can't figure it out because Visual Studio C# Express 2010 doesn't support multi-threaded debugging.