Deprecated: Function eregi() is deprecated in

We just bought a license and we getting serious issues with the use.

We are getting the following errors:

Deprecated: Function eregi() is deprecated in /home/inc/functions.inc.php on line 289

Deprecated: Function eregi() is deprecated in /home/inc/functions.inc.php on line 289

Deprecated: Function eregi() is deprecated in /home/index.php on line 241

And:

Deprecated: Function split() is deprecated in /home/inc/main.mdu on line 139

Any help is really welcome!