Forum 4.2.0 :Error in View Forum Leaders page
 

I have disable the option to show administrators on the 'View Forum Leaders' page .cleared the cache and I get this error:

Warning: ksort() expects parameter 1 to be array, boolean given in [path]/showgroups.php on line 143

Warning: Invalid argument supplied for foreach() in [path]/showgroups.php on line 144

Any idea?