ACE uses the php split function on line 367:
$cats = split(',',get_option("ace_categories_norobots"));
but this function is deprecated in PHP 5.3.13. Hoping this will be fixed in an upcoming update, but for now I've temporarily replaced 'split' with 'preg_split', which seems to have done the trick:
$cats = preg_split(',',get_option("ace_categories_norobots"));
I'm very new to php, so am wondering if this "fix" will mess anything else up, and/or if there's a better solution.
Thanks in advance.