Scripting problem (I think)

When I open a thread with a few responses, about 12 all is fine, if there are lots of replies say over 30, not sure where the cut off point is I get this problem.

Reading from left to right, top POST SUBJECTS.................................POSTED BY.......WHEN then problem is the WHEN section is too far to the right and mixed in with ads. Any ideas please. Windows 7 IE8.