Weird Problem with my Toolbar

Hey guys, got a quick question for you all. Just to setup the scenario, I run Win Xp Pro on my Dell Laptop, and it uses a GeForce II vid card and IE 6.1. This has never happened to me before, but on my website I’m in the process of building, if i hover my mouse over my buttons too quickly, my mouse cursor seems to split into 2, resizes to smaller, then blinks weird. I’ve tested this on multiple computers, and so far only 2 of about the 8 have this problem. Anyone know if IE or WinXP has any known issues with Flash 5 like this? The Site is www.sierrafalls.net if you want to take a look for yourself, though in a perfect world, you wont see the problem at all =P. Thanks in advance for any help provided.