Ouch :S and that's why you should always plug your laptop in before starting any system upgrades. It's changing core files, any corruption or incompleteness is *very* bad there
Which disc did you use to do the repair? If you use the grey disc that's supplied with the mac and reinstalled over the current installation, it'll replace ALL the OS files again, which should fix the problem. If you use a retail disc though, it would only replace the files that needed updating, and probably not fix anything