Push this one to the top as no replies. Only thing that I can think of is that the module (or the slot)is faulty and somehow bridging the contacts - on the assumption that it's seating fully and there's nothing dropped into the slot. I can understand your reluctance to retry it!. Try putting your good module into the slot that you tried and see if it works OK (hopefully your machine will still function with the original slot unoccupied). If this is OK then you have narrowed the problem down to the new module. If you don't want to try this again, send it back to your supplier for testing - let his machine catch fire! (Of course, if the new module was reduced to a molten heap in the first instance, retrying doesn't really apply - send it back).
Anyone any better ideas?
Normal disclaimers apply to this advice line!!!!