Opening and saving a map in the mapper will always crash the game when leaving it

[Magnus]

I'm having a problem with the BIS mapper. If I use it to edit a map file, even if I just open one and save it immediately, then when I play the game it will always crash when I leave that map. Also, some critters seem to be missing from the map when I play it in the game. If I play the map in the mapper it works just fine, and it loads the next one as normal when I try to leave.

The error message I get when leaving is:

"The instruction at 004bfa81 referenced memory at xxxxxxxx (this one changes)
The memory could not be read from"

Any ideas?

EDIT:
OMFG I solved the problem!
Do not rename map files after you've saved them. You need to save them in the mapper as the filename they will ultimately have, or do as I did and open them up in a hex editor afterwards and change the string after the first 4 bytes so that it matches the filename.

 

[Lexx]

What's your mapper.cfg settings? Never heard of such a problem and never encountered anything remotely similar.

 

[Magnus]

I don't have them here at the moment, but I managed to solve the problem.

In the mapper I had first edited ARTEMPLE.map and saved it as test.map so as not to overwrite the original one. I moved it to my fallout maps folder and renamed it to ARTEMPLE.map, but then it crashed as I described above when I tried to play it. I then opened up the map file in a hex editor and saw that after the first 4 bytes there was a text string that still read "test.map". I changed this to "ARTEMPLE.map" and then it worked.