You might have come across with this type of warning messages. This post will help you to overcome this warning message.This warning is caused by an old (php 4) style of method call using a reference. For example

method ( &$var );

This can be avoided by replacing the above code with method ( $var )

You can also set allow_call_time_pass_reference to true in your php.ini it will go away. they are calling a function that was depreciated.If you don’t have access to modify php.ini file then, You can use a .htaccess file to set php.ini values …

php_value allow_call_time_pass_reference true.

Hope this helps,. Happy coding