Hey, Claeric, is this what you've been doing to the sims3packs?

http://www.moreawesomethanyou.com/smf/index.php/topic,18408.msg535029.html#msg535029

That set-up worked for me on all the most recent stuff.  There's also S3PE, which is what I think what was referred to earlier as JFade's front end.  Not sure.  I've not used that myself.

Other than that, I got nothing, short of redownloading stuff to make sure you don't have a borked file.