When does this happen / what page?

(Note to self: Happens on $sql .= db_string_equal_to('cached_for', $codename) . ' AND ' . db_string_equal_to('identifier', $md5_cache_identifier); seems something funky is going on here. This isn't something I thoroughly tested yet because this condition occurs when persistent cache is not available. I have a cache on all of my systems so I'll need to disable them and use db cache to test this case.)

It was after I created a Theme with the Theme Wizard. I didn't use the Setup Wizard. Can access Admin Zone but nothing on Frontend.

Good to know. This code in caches.php looks messy and might be causing the out of memory issue because it's trying to load too much at once. I'll refactor it.