Site Notification Administration

Hi

I don't know if anybody can point me in the right direction but I'm not receiving any emails when people add a new comment to the gallery.
The test email within the genreral area works fine as do the email for new registrations.
I've also tried to set the notification administration to email me when someone add a new item but no luck.

I've tried one solution form the forum, that is to change the name of the main admin user to another and then set up a new admin user.
This is supposed to tehn send the email to the new admin email but still no luck.

I'm running Gallery 2.3 on a dedicated linux server

Many Thanks