Hello.
It seems that you have switched VirtualPathProvider off. Could you please open your web.config file and if there is following declaration:
<add key="CMSUseVirtualPathProvider" value="false" />
try to change it to:
<add key="CMSUseVirtualPathProvider" value="true" />
If you want to have VirtualPathProvider switched off, you should save virtual objects to disk (SiteManager -> Administration -> System -> Deployment -> Save all virtual object to disk).
Best regards,
Vita Janecek