[fw-general] Zend Cache instance PDO

[Sébastien Couragier - DoYouSoft]

I'm trying to cache with an frontend core and a backend file, an 
instance of a class who extends Zend_Db_Table_Abstract.
I'm getting the following error :
You cannot serialize or unserialize PDO instances
Is it impossible to cache a Zend_Db_Table_Abstract ?