anyone know what's going on?
Yes.
I am using multiple intstalls of IE5 and IE6 on my local computer... so it could be something in their rendering...
Yeah. I guess it could be. IE 5.5 is dead for all intent and purpose. IE6 for all practical purposes may as well be obsolete. Until you can confirm that it doesn't work in any other browser either, diagnosis options may be pretty limited.
I don't need any "you should upgrade" flame
Facts are facts. Service packs for 5.5 are no longer even available, and 6.0 SP1 was last released I believe, in 2005. It might as well be dead. No support for CSS V2, png transparency issues, and a slew of potential security related topics. You already know the answers to your questions, otherwise you wouldn't bother with the disclaimer saying you didn't want to hear what you already knew. If it's out of your hands on your own local computer, I suspect you have little recourse but to suffer.