I've got some ways of knowing how that bug keeps on happening. One of them is miscalculation in the server's CPU. I have vBookie installed on one of my vBulletin forums, and in there, if the winnings increase than 2,147,483,647, which can happen maybe by miscalculations in the CPU(Or in my case were intended as a test), then one gets those horrible amounts of vCash, due to a bug in the vBulletin script. I guess it could be sorted out by using a larger variable in the script, but then again server errors have to be sorted out.