Gary - 2012-08-31

hey there
when i click the upgrade button i get the following:

Failed to upgrade from www.webmin.com : RPM signature verification failed :

rpmdb: Locker is not valid
rpmdb: Unknown locker ID: 22
error: db4 error(22) from db->close: Invalid argument
error: cannot open Packages index using db3 - Invalid argument (22)
error: cannot open Packages database in /var/lib/rpm
rpmdb: Locker is not valid
rpmdb: Unknown locker ID: 24
error: db4 error(22) from db->close: Invalid argument
error: cannot open Packages database in /var/lib/rpm
/tmp/.webmin/209001_2_upgrade.cgi: (SHA1) DSA sha1 md5 (GPG) NOT OK (MISSING KEYS: GPG#11f63c51)

Any ideas?
Cheers
Gary