I had an earlier thread about this some months ago, and I also found another one even older. Both describe the same problem, a broken ad gets stuck in an infinite loop, and everything below the ad fails to load as a result. Well, the problem is back.
What happens is that the addresses adserver.adtech.de and 188.8.131.52 keep accessing each other, and they never get anywhere. I have tried the usually suggested methods to fix it, to no avail. Clearing cookies and other private data did not prevent the problem. Java was disabled to begin with. The only way I've been able to access the forum at all is by blocking the offending address. I'm aware this is a solution to the symptom, not the problem, but nothing else I tried would work.
This affected Firefox and Safari, both on Macintosh OSX and Windows XP.