IO,
I can log in to pprune on FF and IE6, both as a mod and a "normal" user without experiencing any problems. I can see the google ads (or not) as appropriate.
I suspect that if there were a generic problem we would be swamped with complaints.
There may be a plug-in or configuration setting in your IE6 that is throwing a wobbly.
Try a different browser for testing - you might get to like it more than IE6!
SD