Check out all the other threads under "mouse slips." They'll provide you with hours of reading...
Accidental piece movement

I think that you can turn confirmations on, but the ability to optionally turn drag-and-drop or click-to-move off isn't a bad idea either.

Don't feel bad. I have 137 losses due to mouse slips. The other two losses were due to my not feeling well.

My mouse slips are due simply to the fact that the touch pad on my laptop is so worn it does what it wants at times. But really whats the big deal? If the worst i have to deal with is some lost online chess games then life is good!
Has anyone experienced same problem? you have one piece selected then accidentally click on nearbuy square and the piece moves. I do that all the time, it's quite frustrating to lose a game due to accidental moves. I think, for PC version of the game, only drag and drop interaction should be enabled. Or even better, optional confirmation box, that requires to confirm each move. What do you think?