I'm not tech savvy guy, but wasn't there a way to prevent this mess???
Like several servers or anything?
You can only really use several servers for the website itself. The actual order matching need to be done on a single processor detached from the front end.
I've no idea how MTGox is run, but it's more than likely that adding more servers is not a trivial task due to the inherriant single nature task of order matching.... particularly if they've done some terrible job of integrating the order entry code (php most likely) with the order matching code (more php... lets hope not....).
That is of course assuming that the order matching is being done properly. As other people have commented about other exchanges, there are some wildly bizzare (and unfair darn right illegal) order matching algorithms being used, so it might be in the case for MTGox that they could just add extra servers and hope that no two buys hit the same sell (or vice versa).