I do Folding@Home (with a different group, sorry), and I recently discovered that I had a unit that wouldn't send for two weeks straight. Researching, I discovered that the version I was using (5.03 or something) was pretty outdated. Apparently 6.20 came out in like August 2008, and the newest version 6.23 came out in December. I don't really know if having the old version was responsible for my problems or not, but I figure if they have an updated version, they probably would prefer that I use it. If you're not sure what version of F@H you're using, you can right click the system tray icon and choose Status -> Log File, or search your computer for a file called FAHlog.txt. When you open that file, it will tell the version you're using somewhere near the top.