Mail Notifications problem


Hi ,

I’ve installed nagios on red hat linux 9 and its working fine except for notifications.
I’ve installed nullmailer for forwarding mail to smtp server.
When i forward mail using root, i receive the mail on my account but when su - nagios , i receive the following error message:
-sh-2.05b$ nullmailer-queue: Could not open temporary file for writing

Thanks and Regards