Here's the W3C's article on Doctypes click here including a link to valid DTDs click here. You should probably use the one for HTML 4.01 Transitional.
It is only height that the validator doesn't like, I think that you can probably just get rid of it without altering the layout because the layout doesn't fill the screen anyway. The widths will be OK if you put quotes around them. Add an alt="QEHS badge" (for instance) to the image and escape the ampersand (&) in the "getfreebb.com" line (i.e. replace "&" with "&").
Add the DTD to the top then make those few amendments to your code and you'll be OK. Once you've done that try it again in Opera, if it still looks wrong come back to us.