Hmm....I got no idea. I'm using Explorer too and am running fine (I actually have 3 PCs here at work, no problems on any of them). You should maybe start a thread asking if anyone else has seen this problem.
Usually when you see this problem, it's because your PC is low on virtual memory (usually older PCs where you have a bunch of crap installed on them). Most of the time when this is the case, rebooting will clear up that memory and allow all the smilies, etc. to load up.