eNewsletter bounce email settings returning fatal error

Hi, I am trying to setup eNewsletter and having some dramas with the bounce email settings. I have created another email address and have triple checked the settings. But i keep getting this error.

<b>Fatal error</b>: Call to undefined function imap_open() in <b>/home/content/79/9189979/html/wp-content/plugins/e-newsletter/e-newsletter.php</b> on line <b>1296</b>
Any ideas on whats going on? Is this another problem with godaddys over zealous email security.
Thanks in advance.