When going from a manual update to a urpmi update you can not install any new mondules due to ill written %pre statements in the rpm's.
-----------------------------
This Webmin module is already installed on your system.
error: %pre(wbt-virtual-server-theme-4.0-1.noarch) scriptlet failed, exit status 1
error: install: %pre scriptlet failed (2), skipping wbt-virtual-server-theme-4.0-1
This Webmin module is already installed on your system.
error: %pre(wbm-virtual-server-3.39-1.noarch) scriptlet failed, exit status 1
error: install: %pre scriptlet failed (2), skipping wbm-virtual-server-3.39-1
------------------------------
The only way I have been able to update through urpmi is by using the --noscripts switch.
This is only needed the first time you go from a manual install to a urpmi one. One the package has been installed once you will not have this error, I think :)