I'm having a few problems with silverstripe and the CMS with errors that I don't understand. Also have found that the site doesn't function properly when viewed using Chrome and won't even open when viewed with firefox.
Is it possible for one of the SS team to help me determine whether it's an SS problem, a CMS problem, a webhost problem or a problem with the operator (me in this case).
I think it would help a lot if you would tell us what these errors are that you're getting. If no errors show up, try to add the following in mysite/_config.php
If you get a blank page, look for errors in the webservers php error log (only when it happens in all browsers, otherwise it's not a php issue). For more information about debugging SilverStripe, read here: http://doc.silverstripe.com/doku.php?id=debugging
I'm sure if you go through [url=http://silverstripe.com/support/]SilverStripe Ltd Suppoert[/url], they'll be willing to help for $$$ ;P - but post the error and you'll probably get the solution for frees.
Btw, I've seen this before where xhtml is specified but something else is supplied - in which case, I'd put money on it being your theme [ie Templates] causing the issue.