Yes I know some of the skins have problems in IE 6. IE 6 is a pain, I wish everyone would upgrade to IE 7 or use Firefox.
I did try to support IE 6 but some skins have some problems in IE 6 and I'm not really very motivated to work on fixing all of them as it can eat up a lot of time. I already put in a good deal of time trying to make things work right in IE 6.
If you want to try it yourself, you can put css in the IESpecific.css file and it will affect only IE6 and will override css from the main files. If you fix some of these please send the updated IESpecific.css file to me.
Else pick a skin that already works better in IE 6
Else someone who feels IE 6 support is very important can pay me to work on improving any specific skins they care about.