Try to delete these files:
1- groups.cache, accesory.cache and cigen.package files all located in c/mydocuments/eagames/thesims2 folder
2- go in the c/mydocuments/eagames/thesims2/thumbnails folder and delete the CASthumbnail.package one, just this one, not the other ones
Delete those files while neither the game or bodyshop are running.
When this is done, try Bodyshop again. If that does not help and you recently added new cc in your game, one might be corrupted, delete the new stuff you added.
I have made it a habit to do so everytime before I start Body Shop and the game. It works fine:)