call_user_func_array() Error

Hi,

When I install and activate your plugin I get the following error:

Warning: call_user_func_array() expects parameter 1 to be a valid callback, no array or string given in /home/tiffdemohostserv/public_html/HairandSpa/wp-includes/class-wp-hook.php on line 298

Warning: Cannot modify header information – headers already sent by (output started at /home/tiffdemohostserv/public_html/HairandSpa/wp-includes/class-wp-hook.php:298) in /home/tiffdemohostserv/public_html/HairandSpa/wp-includes/pluggable.php on line 1179

Do you know how to fix this?

Thanks for your time.