Warning: call_user_func_array() expects parameter 1 to be a valid callback, function 'wp_my_admin_enqueue_scripts' not found or invalid function name in /mnt/data/vhosts/casite-961871.cloudaccess.net/httpdocs/wp-includes/class-wp-hook.php on line 286
This means you have a function named
wp_my_admin_enqueue_scripts hooked to an action, either in your theme or a plugin, but that function name is not available to WordPress for some reason.
When that action fires, any functions "hooked" to it are executed by WordPress. If one of the hooked functions is not available, this is the error presented.
For example, in the sample code below the function named
sc_corporate_widgets_init is executed when WordPress fires the
add_action( 'widgets_init', 'sc_corporate_widgets_init' );
Make sure you do not have a spelling error with a function name. They must match exactly in order to prevent this error.
This error means that you have a wrong action (hook). meaning the code is trying to call a function that does not exists. But, from the path the error is coming from, I think: a) you may have tried to change the core code b) or more likley that your WordPress install is not complete, and you are missing files.