OK, it was an irregularity (td's cannot technically directly house the slideshow, use a div instead). Change:
<td class="tdBanner" id="fadeshow1">
Note: In Firefox a TD cannot have the position relative property nor otherwise act as an anchor for the absolutely positioned slides. A DIV can. Other browsers aren't as picky. I'm not sure which are accurate (acting according to standards) but the fix in this and most cases is simple.
<td class="tdBanner"><div id="fadeshow1"></div>