Could not find Pear DB library

[DodgeThis]

Recently i update my ispconfig3 to 3.0.4.4 but now users can't change passwords on squirrelmail webmail.

when they try to change they password squirrelmail shows 'Could not find Pear DB library'

what i can do??
i have used this how to configure the plugins.

I'm using debian squeeze
and used:
http://www.howtoforge.com/perfect-se...ot-ispconfig-3
and
http://www.howtoforge.com/how-to-con...onfig-3-server

Installed packages, channel pear.php.net:
=========================================
Package Version State
Archive_Tar 1.3.7 stable
Auth 1.6.2 stable
Console_Getopt 1.2.3 stable
DB 1.7.14 stable
PEAR 1.9.1 stable
Structures_Graph 1.0.3 stable
XML_Util 1.2.1 stable