Its probably easiest to open up the sim browser in SimPe, once you have selected the character you can verify the number because it gives the file name in plug in view (tab)
I had a problem very similar happen to me and I dont know what causes it. The space gets warped somehow. What I mean is I have noticed that occasionally for whatever reason if I go into build mode and try to do something I get an error about terrain not level or something, then I turn on the elevation cheat and find that an area has mysteriously warped for some reason. Its usually just a tile or two that is dipped and I can straighten it out with the level.
This almost always happened because of ghosts being on the lot, but I seem to remember it happening a few times to lots where I didnt keep the tombstone and I was simply culling certain townies etc..
I am beginning to become a fan of freewill off. I have been using it regularly for skill building and parties. It makes these tasks so much less frustrating eliminating mindless behavior and me screeching, "NO don't do that, bad sim bad!" at the computer like some lunatic. Once I am done though I always have to turn freewill back on lest I accidently kill someone.
The lot debugger is a mod that might help as previously stated. You can find it at the link below, please be sure to read what it does and does not do.
Well since 2jeffs ghost hack doesnt seem to work for me, (I tell it to only scare knowledge sims and the ghost goes away forever until I take the hack out, even though I may have one or more knowledge sims living on the lot) hopefully this will be a viable fix...I think. Hmm...if they are banished back to ther urn/tombstone though then I cant have the knowledge sim go outside to fullfill the ghost want. gah! I have taken to making almost all of the sims knowledge aspiration.
Regarding aspiration points, generally I use move objects on and then fill the attic (or build a special room without doors) with smart milk and thinking caps. Its a good way to use up grams and gramps aspiration points before they kick the bucket. Thus whenever a sim has a kid and its at the toddler stage I set the sim to making mass quanities of smart milk which I store under the house for future use/generations. I set both mom and dad to making it at the same time with freewill off. I can get about 10-12 canisters of smart milk out of them in no time.
Most of my sims are already maxed in skills by first day of teenhood.