Bad result on webform save

here's a strange one:

Referrer:
http://breadboard/forms/ingredient-prices-input-form

This is a webform page that is set to email the submisstion. When submitting results, the following occurs

Message preg_match() expects at least 2 parameters, 1 given in /var/www/vhosts/breadboard.greatharvest.com/httpdocs/sites/all/modules/htmlmail/htmlmail.mail.inc on line 125.

I've disabled the email function, but it would be nice to have it fixed.