This is in WP 3.5. (Not MultiSite)
Gives the following error:
Missing argument 2 for wpdb::prepare(), called in \wp-content\plugins\cpt-onomies\cpt_onomy.php on line 260 and defined in \wp-includes\wp-db.php on line 990
Looks like it is missing a second argument.
I'm working with another plugin author. Same thing. Everything is fine in WP 3.4.2 but getting errors in WP 3.5.
Let me know if you need more info.