I don't use my PC much any more, my sims game is on a Mac. By the looks of the extension (XCPT) (MDMP) I think they may be error crash files. I would think they could be safely deleted but I would wait until someone with more knowledgable than I to confirm. You could also try moving them out of the folder to your desktop before deleting, start up your game to confirm everything is working fine, if so they should be safe to delete.
Are you able to open them, possibly in notepad or a text editor program to take a look?
edit: actually I just looked in my folder (on a mac) and I have some also. I am going to do some research on these to see what I come up with.