[SOLVED] Error: Function eregi() is deprecated

Hi,

Recently, the error "Function eregi() is deprecated" suddenly cropped up, after I uploaded the Wordpress website I was working on on my laptop onto my online server.

Function eregi() is deprecated in /data/web/<domain xxx>/wp-content/themes/atahualpa/functions/bfa_ata_admin.php on line 368

I'm now not able to edit quite a number of the Atahualpa options because of this error above.

I'm using the latest versions of Wordpress (3.2.1) and Atahualpa (3.6.7), and some digging online seems to indicate that this has something to do with the PHP server version. I've checked, and these are the specs of my web server:

Apache/2.2.17 (FreeBSD) mod_ssl/2.2.17 OpenSSL/0.9.8n DAV/2 PHP/5.3.5 with Suhosin-Patch

Has anyone else experienced this, and what is the way to resolve this?

Thanks!