I don't really know about the launcher constantly disappearing, but you can update your game (which it looks like you need to) using the manual patch.
You can find your game version by hovering over the base game icon with the mouse. Let me know what it is, it should be 1.48 as far as I'm aware, because you're on a MAC.
See here: http://answers.ea.com/t5/The-Sims-3/FAQ-Current-Patch-1-50-Manual-links-and-more/td-p/67858
You'll note that (to quote) "Mac Patch 1.50 is NOT out yet". Read that part carefully
Welcome to the Answer HQ!
Edit: I found this, apparantly it helps find your game version on a MAC: http://bluebellflora.com/ts3-on-a-mac/checking-which-patch-version-youre-running
I have just tried re-installing all my expansion and stuff packs again and this has just come up when I tried to install sims 3 high end loft stuff pack
the sims 3 version installed is more recent than expected. the sims 3 high end loft stuff could be incompatible. make sure you get all updates before playing.
what does this even mean!! someone please help me
