This puzzled me for a while and I have seen others post similar issues…
Turns out that there is actually an underling error but when Yii attempts to display the error it tries to use the theme class which has not been loaded yet.
In my case the first error is "Declaration of BeavBaseActiveRecord::save() should be compatible with that of CActiveRecord::save()", but in trying to display this error an autoload attempt is made to load CTheme - which fails.
The stack to the issue is
A quick fix for this would be to modify CThemeManager->getTheme:60
I am using the HEAD of SVN…