SysAdminGear

This post will probably help you to fix an error occurring when you try to upgrade some package like this:

rpmdb: unable to join the environment
error: db4 error(11) from dbenv->open: Resource temporarily unavailable
error: cannot open Packages index using db3 - Resource temporarily unavailable (11)
error: cannot open Packages database in /var/lib/rpm
warning: /root/webmin-1.360-1.noarch.rpm: V3 DSA signature: NOKEY, key ID 11f63c51
rpmdb: unable to join the environment
error: db4 error(11) from dbenv->open: Resource temporarily unavailable
error: cannot open Packages database in /var/lib/rpm
rpmdb: unable to join the environment
error: db4 error(11) from dbenv->open: Resource temporarily unavailable
error: cannot open Packages database in /var/lib/rpm

How To Fix:

Remove Old Lock Files running this command:
# rm -f /var/lib/rpm/__db*

Now you have to rebuild RPM database:
# rpm -vv --rebuilddb

It should be fine now, if you want you can read more information at: http://www.rpm.org/hintskinks/repairdb/