I'm having a lot of problems with Stumbleupon of late. More often then not giving the thumbs up has no effect, or if that works I cannot add a comment. Often it won't let me add friends or do any other normal functions. I usually have to copy the code directly into the toolbar!
And this happens on all three computers in our house!!! If anyone wants to add me as a friend I will endeavor to reciprocate as soon as it lets me (same user name). David365