Quote: "Cannot find mesh at line *"
Mesh info(location) is in the fpe file, not in the x file. While it's true that sometimes you need to change the location of the texture and mesh files in the fpe, most if not all of the files on my site were tested in fpsc by me and others and were working at the time of posting. I've certainly made mistakes (I think) but I test every file before I post it.
Now I know they are not 100% and someone else brought up an issue this morning that has been fixed. If however you are having an issue with as many as you say, it's because you are not inserting the files in the proper folders, which causes you to have to change the locations in the fpe file. If you do find some that are wrong however, I would appreciate that info so I can fix them.
For future reference, if you have an issue with an entity, look at the location of it's mesh and texture files in the fpe, and make sure the files are actually in the location it says they are.
Best.
I'm sorry, my answers are limited. You must ask the right question.