Thanks for finding the problem so quickly Jason.
I really appreciate your help.
Trouble I have is I get a layout which seems to work, and when it starts to break down, I find it difficult to debug.
Even using Firebug and Chrome, I couldn't find the issue.
It seems that most of my issues are css related, perhaps because I relied too much on css sculptor when first starting out.
If anyone can recommend a good css course or books/ materials, I would be interested