Form error in Firefox

I built a standard form (post) and stuck it on a .asp page.
It works fine with IE, and works eventually with Firefox, but Firefox seems to just 'shift' the page over when I submit - and will do this 3 or 4 times before actually responding to the button.
Try it out: yepdata.com/webtime/newaccount.asp
Any thoughts why?
note- yeah, I know there's no asp on the page...
my host doesn't support ssi, so I sneak my includes in.
Dan