For a start you're including inline styles as well as references to the stylesheet (with id and class in the div tags), maybe that has something to do with it.. I think it would be best to either stick to one or the other in order to avoid confusion.
Also are you sure that in the first div tag; that 'id="bannerc"' should be an id and not a class (I couldn't tell you without looking at your CSS code.)
Also make sure that you have actually included the stylesheet!
You may have forgotten to link it to the HTML page.
Sorry if I'm not really helping. I'm just throwing a few ideas at you so you can look through the code to see what may be wrong without having to post the whole thing online.
I'm off for the evening now anyway.
If you're still having problems just email me and I'll take a look ASAP.
(cobra_kai[at]ntlworld.com)