I couldn’t quote grasp what “even line” you were talking about as those drawings look much the same to me. The only difference I can see is that the left side is wider in iE6 because you have overstated the width here:
I can’t see any background on the even rows but looking at the code I see you have set the background of the even rows to #f7f7f7. Unfortunately neither my eyes cannot distinguish the difference between #f7f7f7 and #fff and I doubt that anyone else will be able to see it either :).
I’ve changed the background to red so we can see it and attached a screenshot of what I’m seeing in IE6 so you can tell me what needs to be changed (it looks identical to Firefox though).
The image is based on the code when you first posted as you seem to have changed the header in that section for IE6.