I can’t get to your site using the posted URL.
Main problem is, you have XHTML 1.0 Strict as your doctype, while using tables with their style attributes. Here’s a tag reference for XHTML Strict that shows what’s allowed as tags and their attributes:
http://webpageworkshop.co.uk/main/xhtml_reference
Anything else you want to set would have to be moved out to your stylesheet.
The validator provides a fair bit of information about what the issues are. Because you are using the XHTML Strict DocType, you will have to do a bit of research on what is allowed under that specification.
There are a number of references like this: ...the document type you are using does not support that attribute for this element.
Have you validated using the XHTML Transitional doctype at all? If not, perhaps switch to transitional, fix any problems you might find there, and then switch back to strict and re-validate.
