i haven't read the entire thread, but...
if you're having sdcard problems, first thing to look for is
do you have apps installed to sd? if so, don't. uninstall them and reinstall them to internal memory
do you have evernote installed? this has been causing mount problems with other's sdcards.
is your sdcard a class 10? even though i have had no problem with my patriot class 10 card, others have had problems
have you tried formatting the sdcard via the phone? if not, try it, but back up your stuff first.
the camera app shutting down could also be a by-product of your sdcard woes.