After upgrade to Version 12: Undefined property "isPublished"

[bkb]

After upgrade from Plesk Panel 10 for Linux to Version 12 on Debian 6.0 I get the following error upon logging into the Plesk panel:

Any help would be appreciated.

Internal error: Undefined property "isPublished" in object "SB_Site".
Message Undefined property "isPublished" in object "SB_Site".
File Generic.php
Line 33
Type SB_Facade_Exception_Generic