Thanks for the reply Jholder, I found this post
Zimbra and FC6 which explains a work around for the "Require tty to run sudo"
I'm going to post here the work around for future reference.
Since FC6 (hence RHEL5 and CentOS5 too) Redhat added a new option to the sudoers file:
Defaults requiretty
This new line is the reason we are getting the "require tty to sun sudo" error.
The work around is opening the sudoers file with visudo ( <- command) and searching for the string requiretty (on vi/vim "/requiretty" + enter) and comment out the line (on vi/vim "i" for insert mode then add a "#" to comment out the line. then hit ESC key to get out of insert mode and then press ":" + "wq" to save and exit from the file.
now it should all be good!
PS: when I see a post title "Zimbra and FC6" I (and i'm pretty sure other people) would have discarted it since i'm NOT looking for FC6 "issues".
Hopefully since this post now includes CentOS 5, RHEL 5 and FC6 when people do searches this might help them get to the answers quicker.