Internet explorer script error,Scrollbar doesnt work on IM window

Whenever i try to IM a contact in my list or someone is messaging me whenever im online there is a box that pops up telling that there is an internet explorer script error blahblahblah... and when i click either yes or no, the font style and size just turns out to be the default setting.. and the scrollbar doesn't seem to work.. I cant also see the rest of the messages when the IM window is full.. Please help me out on these. Thanks. Godbless.