I've ran into the same problem and Samba module wouldn't show in my webmin list of servers. It wouldn't show samba modules, in my case, and it wouldn't install webmin-samba modules manually. Removed and re-installed the webmin app but had no luck until I've read the forum
http://www.turnkeylinux.org/forum/suppo ... ment-10983 with apossible solution that I, later, found to work for me!
This goes to the newbies, like me, out there:
- I'm running SL-Linux 6.3 2.6.32-279.14.1.el6.x86_64 with Samba version 3.5.10-125.el Webmin 1.610
- Going to Webmin modules, click Webmin > Webmin Configuration and there should be an icon Upgrade Webmin

- webmin cinfiguration module
- webmin_module.png (154.19 KiB) Viewed 5524 times

- webmin upgrade even if latest version installed check box must be checked
- webmin_upgrade.png (18.37 KiB) Viewed 5524 times
- Don't forget to check "Upgrade even if new version is the same or older?" box to make sure your webmin will upgrade no matter what version you have, even if it is the latest one.
- Logout and log back in with root account
- You're done!
Thanks to Eric on
http://www.turnkeylinux.org/forum/suppo ... ment-10983 , nicely done on sharing your expertise!!!