strange wp-admin access issue

I have the following very strange situation:

When I try to login, the login screen comes up, I enter the login and password, but after entering the password I get a 404. The strange thing is that after I reload home page of the blog, I can see the admin menu on the top of the screen and I can enter any menu, except for the “dashboard home”, wp-admin/index.php

There’s an error_log with tons of messages in public_html/wp-admin, but I can’t make heads or tales of it. Any guidance would be appreciated.

I have tried re-installing wp via the updates menu, I checked my htaccess file and I repaired the database using db_manager.