style="margin:auto;" to the problematic iframe or
style="text-align:center;" to it's parent tag.
Tables for content layout
From the looks of your website, you're using tables for the layout of your content.
Tables can only be used for tabular data! Using tables for layout is depricated by all modern standards!
The correct way to program the layout of your site is using css
Using tables can bring about a whole pile of problems for your site.
You should never
use tables for layout.
Also around line 350, there is this -
However all your other tags are lowercase. One of the main things to try and keep to is consistancy!
(P.s. You should never use uppercase tags anyway)
Also, you're using font tags; in modern standards they're depricated.
You have to use <tag style=""></tag> where tag is the tag of your choice (I normally use span tags to do what a font tag would do).
At least you're not using <center> tags!