Deleting profile fields breaks advanced user filter

Steps to reproduce:

1. Create a custom profile field
2. In Site Configuration -> Advanced User, choose the custom field under Profile module special settings and save.
3. Delete the custom field.
4. View User Management -> Users -> Advanced to see an SQL error caused by Advanced User attempting to gather information about a field which isn't there.

Workaround:
Go back to Advanced User's configuration and re-save the Profile module special settings.