I cannot access the upgrade page

I have two blogs and both have needed updating for some time. They both used the same theme and were running a version of WP in the 2.2 range. I decided to upgrade to 2.5 today.

My main blog, a fitness blog, went smoothly.

I installed and activated Maintenance Mode first. Then I deleted include and admin and uploaded the 2.5 versions of those files, but not before backing both my files and database, AND deactivating all my plugins.

Once I tried going to the upgrade page at http://www.mysite.com/wordpress/wp-admin/upgrade.php, I saw the standard upgrade button and it worked just fine. Whew! My other blog is a different story.

I used the same procedure as before, making sure to deactivate my plugins and back up all files and DB.

I deleted admin and includes and re-uploaded these folders from the 2.5 version I used in the first upgrade. I overwrote all other files accept the confige file and when I tried to access http://www.mysite2.com/wordpress/wp-admin/upgrade.php all I got was this:

Maintenance Mode
Welcome To MySIte2 is currently undergoing scheduled maintenance.
Please try back in 60 minutes.
Sorry for the inconvenience.

I could not access the upgrade.php file and no matter what I did the Maintenance Mode splash page kept appearing. http://www.mysite2.com/wordpress/wp-admin/upgrade.php just never took me to the upgrade page.

I tried the whole procedure again, and got the same result.

What have I done wrong?