This is just from taking a quick look at your site:

1. Your table widths are way to big. It is good design practice to never make a page bigger than 1024 pixels in width (yours is 1200).
2. You have a few misspellings in your table tags. You may want to review those.
3. You have a ton of colspan's, but the numbers on them do not add up. I don't know if you know what a colspan is or not so I would suggest that you review a table tutorial and adjust them correctly.
4. I counted as least one "gap" caused by a table row that simply had a colspan in it and nothing more.