[Plugin: PhotoContest Plugin] Fatal error: Call to undefined function: mb_ereg_replace()

When you get the following error:

Fatal error: Call to undefined function: mb_ereg_replace() in /wp-content/plugins/wp-photocontest/lib/wp-photocontest.functions.php on line 48.

please update to version 1.0.1 or compile php with mbstrings
(see: http://www.php.net/manual/en/mbstring.installation.php)