Administrator Login Problems after PHP & MySQL upgrade

This is the story on how I upgraded AG from version 2.2 to version 2.3.4...

...so I had AG 2.2...

=== PROBLEM: ===
Sunddenly my Admin Password didn'y work any more,
I knew from my hosting provider that they just upgraded mySQL from v. 4.0 to 4.1.x and PHP from version 4.3.x to 4.4.x.

They tried to solve access problem "changing format of passwords with one compatible", so I was able to enter... but whenever I click on every menu item it brings me back to login page !

Same problem of 4664 post.

So I tried to change LAST_VISIT field of the book_auth table in the database as int (11).
It didn't work. So I setted again as TIMESTAMP.

Looking at post 5001 I tried www.carbonize.co.uk/reset.zip but it returned an error that it was unable to reset passwords (SQL pw was absolutely correct, otherwise the error is different).

Then I tried to reset with SQL:
delete from book_auth;
INSERT INTO book_auth VALUES (1, 'test', '773359240eb9a1d9', '7d8b85294e2e060b83f596a4fc5561ce', 1058460506);

It resetted password... but unable to use "test" "123", so I tried again with
www.carbonize.co.uk/reset.zip AND IT RESETTED PASSWORD TO MY ONES.

But the first problem wasn't fitted, no way to use Easy Admin and the other ADMIN menu items.

=== SOLUTION: from 2.2 to 2.3.1 ===
Upgrade to 2.3.1 version.... IT WORKS FINE !

Since I was already working on it I decided to upgrade to 2.3.4.
Again appeared the Administrator Problem...

=== SOLUTION: from 2.3.1 to 2.3.4 ===
THIS TIME trying to change LAST_VISIT field of the book_auth table in the database as int (11), I got back my Administrator Control...

Hmmmm something odd there as 2.3.x should not work with 2.2 database. You should get logged out as soon as you click a link in Admin.