Yep - a program tries to write to a segment of RAM that's already in use, which would overwrite it. So, to prevent this, I believe it's the kernel or some part or appendage of it *g*, which basically shuts the offending program down. I don't know that it's bad memory *management*, so much as bad code in the particular app making it do stupid stuff. The fact that the fault is *caught* is actually good memory management, but I could be off there.
*awaits gurus for more complete explanation*