site not showing correct in FF or opera

Hi,
I am starting to design a site. The Navigation shows up fine in IE, but not in FF or opera.
The css and html both show the correct color, but its not going the full length of the row in FF or opera.
Can somebody please help?
go to
http://www.cpgc.taupedesign.com/ and click on the "copy index" tab. Thanks

It's showing in FF and Opera (and Chrome) exactly as you wrote it. IE is the problem here despite it showing what you want (and IE will always be the problem). Validate and fix your html errors but you can't give a floated element 100% width because it's removed from the normal flow and has no parent to reference in this case.

Never, ever trust IE to do anything right.

Thank you Dr. Howard,
I did put the page through a validator and all the errors relate to the line

<table width= 100% table border="0" cellspacing="0" cellpadding="0">

If I remove the <table width= 100% part, the tabs don't stay in a straight line, but go on top of each other.
If I remove the whole line, well all hell just breaks out.
How would you code this please? I know it is probably simple, but I am flummoxed.
Regards,
Cambridge 77