I've found some problem with database when I have tried to update hostname (optional) but its the same thing when i try to update anything:

"SQL Error: Could not execute query in /usr/local/centovacast/system/class_DBObject.php:390
Query:    UPDATE rpchosts SET `ipaddress`="127.0.0.1",`port`="2198",`authkey`="DELETED",`title`="Local server",`isrelay`="1",`ismaster`="1",`defaultip`=DELETED",`daemontype`="RPC",`hostname`="DELETED" WHERE id=1
Error:   Unknown column 'hostname' in 'field list'
Call:   $SQL->misc_query()"

Right, there was another client (perhaps you?) who reported that the database update did not get applied in the latest build, and it appears you were affected by that here too.

To fix it manually you can run:
ALTER TABLE rpchosts ADD hostname VARCHAR(255) NOT NULL DEFAULT '';

Figuring out why this didn't apply automatically is one of the few remaining outstanding issues in the beta2 issue tracker.