fixing css for ie6 need help!

Answer 1

ok, after 2 hours of work, i gave up useing DD_roundies,

it just doesn't work well with combination with the Tabs UI.

Then I tried another plugin which I know should work, and tested on:
IE6, IE7, FF3

all works well!

See demo here

I've also modified your CSS.
put the whole "Corner radius" section on comment. no need for that.

Hope this suits your needs :)