Are you calling SDL_Quit() yourself AND using atexit(SDL_Quit) by any chance?

my atexit() line is:

atexit(cleanup);

then I have a function which calls the uninitalizers for the three libraries I am using: SDL, SDL_ttf, SDL_mixer... so no I am not calling the SDL_Exit() function twice...

try letting go if the interfaces in the opposite order you aquired them

ex. initilaize
SDL
TTF
AUDIO

let go this way

AUDIO
TTF
SDL

That didn't work

What is called before the HandleMouse routine?
Maybe the function before it messes up the stack.
Just an idea.

Also remember that SDL uses multiple threads, so when you look at your call stack, to find where it crashes, there may be more than one call stack. For the same reason, it seems to me that a printf may not be a reliable way to test were a program crashes, because the problem could be in another thread.

AFAIK, SDL doesn't use more than one thread unless you make them yourself. I could be wrong, though. Mind directing me to a doc?

Kelly G's points are valid if you are using thread.