This one is still bothering me! Using linked tables Access I noticed the length of the email address field is 0 and the content is "". I think it should be null in both cases. Of couse changing the email field to null (for relevant members) fixes the problem.
BTW I also changed the database default of the email field to null just for kicks.
Despite all of this, all new members are being created by the registration process with an email address of "" length 0. And further, records previously corrected by me to null are being changed to this value on update of an non-connected field (name or whetever) in the profile.
Borg, given this, I do not believe the database is corrupt - can I provide you with any further info ?