Okie dokies.
After encountering the problem once more(In the span of one day no less!) I went to work to find out more about it.
After some forum-delving and database editing I finally found out that I had an npc_faction entry which id-column exceeded the limit of 49999. A quick fix there, some editing of other entries in npc_faction_entries and faction_list later on and I'm back up and running.
Here's the link to the thread that really tipped me off about it:
HELP!!!.. had a slight accident!
Culex