Can not upgrade!

I had originally installed 2.4 on my blog @ http://meta-human.net/blog/
When the new update came through, I was able to get it updated.
Now the problem remains with 2.5.1. I do not seem to be able to upgrade.
I tried it thrice yesterday. Did not go through. Good that I had backups.

This what I do-
1. Deactivate all the plugins.
2. Backup/rename wp-admin/wp-content/wp-includes.
3. Save wp-config.php on my computer.
4. Upload the newer files to the server via FTP.
5. Go to http://meta-human.net/myadmindirectory/upgrade.php

Just once was I able to upgrade the database. After that, thrice no success. Everytime I go to wp-admin/upgrade.php, I get errors in some file or the other.
This time, it was pointing towards wp-settings.php.
Been trying to update for 2 days now. 🙁