I have corrected the xhtml and it now has no warnings or errors. The css has errors to do with transparency but no others and some warning about colours. I will try and work out what those ones mean. I particularly want to keep the transparency in. It appears to work in the browsers I am targetting for my webpages so far.. I have had to remove the ad code from burst media as the old code was not xhmtl compliant (as far as I can tell..) and the new code is unliked by safari on mac.. I will write to them seperately and ask advice about their code!
How important are the warnings about colour such as
Line : 76 (Level : 1) You have no background-color with your color : #smlflyingsnakedragon
Line : 76 (Level : 1) Same colors for color and background-color in two contexts #black and #smlflyingsnakedragon
Line : 76 (Level : 1) Same colors for color and background-color in two contexts #black2 and #smlflyingsnakedragon
Line : 76 (Level : 1) Same colors for color and background-color in two contexts #black and #smlflyingsnakedragon?

Thanks for advice

Back to walking dogs and working on rediting all those old gifs to be transparent!