Initializes and starts. Quickly gets to "remaining one of two", but never progresses. I have a pretty large user profile collection, 50000 or so.

These errors are in the log repeatedly

array_shift() expects parameter 1 to be array, null given in /var/www/language-exchanges/sites/default/modules/profile_migrate/profile_migrate.module on line 428.

Division by zero in /var/www/language-exchanges/sites/default/modules/profile_migrate/profile_migrate.module on line 491.