Error when installing E-Newsletter

I get this error at the top of my page when I activate the e-newsletter plugin:

Warning: session_start() [function.session-start]: open(/var/chroot/home/content/79/5300379/tmp/sess_va7r0vinnhivf89ikptlnlo891, O_RDWR) failed: No such file or directory (2) in /home/content/79/5300379/html/wp-content/plugins/e-newsletter/e-newsletter.php on line 1484

Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at /home/content/79/5300379/html/wp-content/plugins/e-newsletter/e-newsletter.php:1484) in /home/content/79/5300379/html/wp-content/plugins/e-newsletter/e-newsletter.php on line 1484

Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at /home/content/79/5300379/html/wp-content/plugins/e-newsletter/e-newsletter.php:1484) in /home/content/79/5300379/html/wp-content/plugins/e-newsletter/e-newsletter.php on line 1484

Any insight would be great!

Thanks!

Megan