It is not an error, it is just an information message. The reason you are seeing it is because your site error reporting is turned up too high, you need to edit the global configuration for your site, under server error reporting turn it to 'none'. You should do this anyway it is a security risk to have it turned on.
The funtion ereg() is deprecated in PHP 5.3, this just means that it has been superseded by a more recent function, but it still works.
Now you have reminded us of this I will make sure that this code is updated in a future release.