gaps? about 1 or 2 pxls wide? If so I think I know what your talking about.

I believe it's cell spaceing and cell padding that's giving you the issues, go the the html coding and go to the body tag and type

cellspaceing="0" cellpadding="0"
If that's the problem then it's fixed :P if not dunno, I'm not good with frames <_<.

Good luck.