Coloured cells in firefox & netscape

Hi,

I am new to Dreamweaver and have been experiencing some problems with my
website www.bethhockley.com and was hoping you could help.

My site uses tables, I have coloured the background of some of the cells. When
creating my site I tested it in safari, where the coloured cells worked ok.
However, when my website is viewed in netscape or firefox the coloured cells do
not work.

I understand that sites will look different in different browsers, but as one
of the coloured backgrounds acts as my navigation and others act as backgrounds
for white text, I really need to fix this problem.

Thanks