Okay, this is a strange one!!
I just had a look at you code; nothing obviously wrong, but I'm tired so i only scanned over it briefly.
What browser are you viewing it with? I used F'fox 1.5 and it did not display correctly. No joy in Opera either. Nor in IE.
However... I brought up the browser issue because I just created a test page on my freespace click here and this has the same problem except in IE, in which it looks correct.
I'll get back to you tomorow if I figure it out.