Error while posting articles

[Arin Basu]

I created this new journal at:

http:.//jimi.org/journal/wordpress/

and used annotum base as the theme.

Unfortunately, I cannot seem to add any article to the theme. Attempting to add an article returns the following message (fatal error):

Fatal error: Call to undefined function mb_eregi() in /home/ijmibhat/public_html/journal/wordpress/wp-content/themes/annotum-base/functions/phpquery/phpquery.php on line 1440

What do I need to do to correct this error?

Arindam Basu