Download zabbix-2.0.9 source from their website and replace the contents of zabbix-2.0.9/frontend/php/ into /usr/share/zabbix/ (rename the old zabbix to zabbixold). Then log into the web interface. It will have you go through all the config again, it will generate a zabbix.conf.php file for you to copy into this directiory, but once a connection is established to the databse it should restore your frontend without the error.
I have this problem to.
WORKAROUND:
Download zabbix-2.0.9 source from their website and replace the contents of zabbix- 2.0.9/frontend/ php/ into /usr/share/zabbix/ (rename the old zabbix to zabbixold). Then log into the web interface. It will have you go through all the config again, it will generate a zabbix.conf.php file for you to copy into this directiory, but once a connection is established to the databse it should restore your frontend without the error.