In my database, the full admin rights are: 1961343989. Without actually decipyphering the numbers I cannot say if yours are wrong, though. All that really matters is one bit that is the ADMIN_RIGHTS value.
I am not sure changing hashes is of any use. Unless it was an old hash for the same user with different password there is no way it would work.
One thing you can try is to remove the admin from the database. This will promote one of the lessor rights users to full admin. So if this is the one you can log in as, you can then re-create the full admin user.
I really do not know what could have gone wrong that some users work and others do not. The algorythm for hashing would be the same in all cases.