Error Message

Hi there

Wondered if anyone could help?

I started getting this error message on every page of my site https://www.utilitymedialink.com

Deprecated: Call-time pass-by-reference has been deprecated; If you would like to pass it by reference, modify the declaration of apply_filters(). If you would like to enable call-time pass-by-reference, you can set allow_call_time_pass_reference to true in your INI file in /home2/aacoverc/public_html/utilitymedialink.com/wp-content/themes/mystique/core/AtomWidgetText.php on line 142

I think it is to do with the theme. I was previously on WP version 3, upgraded to 4.1 and it is still there.

Any ideas.

Many thanks

Wulfy