Top Right html problem

Hi my site www.in2town.co.uk is having major problems with the top right module. I have tried putting in an advert into the following page in that position http://www.in2town.co.uk/celebrities-are-using-trance-band-hypno-band-to-lose-weight but it worked once just fine but when i then tried to do another advert in the same position on another page it did not work and the origial advert in that position vanished.

Can anyone please let me know what i have done wrong please and how to solve it