Hello,
DotNetNuke itself produces code which does not validate, so you need to make tweaks to the core code of DNN in order to have a site that fully validates.
First steps are to ensure your skin and CSS code fully validates
2nd - remove all of the invalid CSS code that comes with DNN in the default.css file
- I have written about reducing the code in the default.css file here:
http://www.skinningtoolkit.com/ARTI...fault.aspxYour next step is to edit the core code of DNN. - There is a tutorial on how to do this with DNN3.x by Tim O'Brien but there currently is not one for DNN4.x the principles will be similar though. - You need to register with the website and login in order to see the tutorial.
http://www.obrienit.seYou may also find it useful to read this interview with Tim covering skinning and validation:
http://www.dnncreative.com/tabid/25...fault.aspx