There is a bug in the plugin when attempting to change the port used for sending email. Currently, line 18 reads as follows:
if (defined('WP_SMTP_PORT') && is_int(WP_SMTP_USER)) {
It needs to be changed to read as follows:
if (defined('WP_SMTP_PORT') && is_int(WP_SMTP_PORT)) {
I can submit an SVN patch if you'd like, but I believe this should be sufficient to fix the problem.
