If you really want me to find errors then I shall, the Document Type Definition (DTD) reports Strict XHTML 1.0 on the first page whereas the label says XHTML 1.1.
It would have been more wise to ask "how you may improve the site" rather an get people to find errors, because they will make it their objective .
It would have been preferable to label the navigation menu graphics for your portfolio - those two "navigation cones" since you are displaying Web Accessibility Initiative (WAI) Double-A.
Also the interactive "design process" could be bothersome to navigate, try to provide alternatives to the embedded Flash object.
Although your Cascading Style Sheet (CSS) grammar is correct you could have made better use of the 'background-color' and 'color' by making sure there was a better colour contrast.
Because you have chosen to follow the WAI checklist I would find these points probably would conflict with the checkpoints for 'Double-A'
Those are some of the main points that leapt out when you asked me to find errors...