Error E-newsletter - mkdir() [function.mkdir]: No such file or directory

Dear,

I get the follow error on my site when I try to setup my smtp server. When I click install I get this error.

Warning: mkdir() [function.mkdir]: No such file or directory in /home/wouteqp23/domains/backpackbeta.nl/public_html/wp-content/plugins/e-newsletter/email-newsletter-files/class.functions.php on line 2021

Warning: Cannot modify header information - headers already sent by (output started at /home/username/domains/backpackbeta.nl/public_html/wp-content/plugins/e-newsletter/email-newsletter-files/class.functions.php:2021) in /home/username/domains/backpackbeta.nl/public_html/wp-includes/pluggable.php on line 896

Wouter