You have not said what is supposedly wrong with the doctype? I cannot see anything wrong with it, except that, if it is a new site I would suggest it should be coded to HTML5 standards, not HTML 4 (loose). As to the coding in general:
Why is it written using tables? That is a somewhat out-of-date coding style. Nowadays it should be written in DIVs.
Why is it written fixed width? Another out-of-date coding style, which is unsuited to the growing mobile users.
Overall - A very mediocre site that is similar to my own first web site. My excuse for the use of obsolete code is that I wrote it five years ago, and I've subsequently rewritten it from scratch! What is your excuse?