yum update
Loading "installonlyn" plugin
Setting up Update Process
Setting up repositories
Reading repository metadata in from local files
Resolving Dependencies
–> Populating transaction set with selected packages. Please wait.
—> Package kernel.i686 0:2.6.18-53.1.13.el5 set to be installed
—> Package wbm-virtual-server.noarch 0:3.52.gpl-2 set to be updated
–> Running transaction check

Dependencies Resolved

Package Arch Version Repository Size

kernel i686 2.6.18-53.1.13.el5 updates 13 M
wbm-virtual-server noarch 3.52.gpl-2 virtualmin-universal 765 k

Transaction Summary

Install 1 Package(s)
Update 1 Package(s)
Remove 0 Package(s)

Total download size: 14 M
Is this ok [y/N]: y
Downloading Packages:

Package wbm-virtual-server-3.52.gpl-2.noarch.rpm is not signed

I too have that problem.I recently installed virtualmin after the webmin update. On the “System Information” home page an update popped up. which it says is unsigned and won’t install.

Edit the virtualmin.repo file. Change gpgcheck=1 to =0

this will let the rpm install.