Cant change dns options in webmin section

[gvocom]

For some reason I cannot add DNS checking option in the admin or WEBMIN administration area.

The expanded error refers to something called 'join' Before my MTA was not working correctly because i had not yet done a #apt-get install file So RIGHT after this I was not able to change this section in the webmin, before this I was now when I try to save the changes i get the following error, any ideas? I have restarted zimbra flushed cache tried different browsers as well, tried this on windows, ubuntu

my server is running the newest version 6, on
Linux version 2.6.26-2-xen-amd64 (Debian 2.6.26-22lenny1) (dannf@debian.org) (gcc version 4.1.3 20080704 (prerelease) (Debian 4.1.2-25)) #1 SMP Wed May 12 18:37:58 UTC 2010


JavaScript error encountered in method
ZaxFormViewController.prototype._saveChangesCallba ck

Message: Object reject_unknown_sender_domain has no method 'join' stack: TypeError: Object reject_unknown_sender_domain has no method