PHP Sendmail errors

[Emohawk]

I keep getting intermittent errors on the mail() command
the error i get is
Warning: mail(): Could not execute mail delivery program '/usr/sbin/sendmail -t -i ' in /

http://www/mobojo.co.uk/newsletter/admin/newsletter.php

on line 460

and its intermittent, is there any way to debug Sendmail at all? to see where it gets stuck?
because it works from the command line, but not through php

 

[ericbrunson]

Does the file /usr/sbin/sendmail exist on the system?

This really doesn't have anything to do with apache, it'd be better suited to the PHP forum.