Problem Grolle

I get the message

Warning: call_user_func_array() expects parameter 1 to be a valid callback, function ‘my_gwolle_gb_admin_reply_header(‘ not found or invalid function name in /customers/9/4/7/heron3050.com/httpd.www/wp-includes/class-wp-hook.php on line 288

Line 288 says

$value = call_user_func_array( $the_[‘function’], array_slice( $args, 0, (int)$the_[‘accepted_args’] ) );

And idea on what is wrong ?

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