I had my first Woohooer error the other day, concerning a cat rather than a Sim (not my family's cat, the family I'm playing don't have any pets). I noticed the above phrase in the error file, and it pops up in other types of error file too. What exactly does it mean?

I believe that means the mod (or game) is being asked to do something with or use a value that is not defined. Cats are sims and resident ones would fall under the purview of Woohooer just as humans do, although of course subject to different kinds of romance and mating patterns meant for their species. This could be coming from a custom woohoo/breeding location (pet house?) or a mod that is not playing well with Woohooer, although our developer can correct me if I'm "meowing" up the wrong tree here.

Usually we can get more clues from the script log, depending on which mod threw it, such as what the sim was supposed to have been doing at the time and which exact action seems to have brought about the error.

http://www.mediafire.com/file/cat4jkw0x ... 6.zip/file

I looked at the file and it seems like the interaction was "give birth", so I'm guessing that was a problem.

The only odd thing I see there is that the cat is not on her home lot at the time she tried to give birth to her litter, but rather is on the world lot? I think we're going to need some help understanding this one.