undefined function force ssl admin wp-setting.php

Yes before I attempted to update from 2.5.1 to 2.7 I deavtivated all of my plug ins. I am wondering if I did the update incorrectly.

Should I have deleted the old files before uploading the new ones?
All I did was transfer the files via FTP. Was it a mistake to transfer the folders rather than opening the folders and transfering each file to the appropriate folder?
Also I believe 2.7 doesn’t have a separate admin file, it is now in the content folder.

Sorry, I guess you really do need to do each update, but they come very frequently and I had some seo files that I knew would get messed up when updating.

the error message also said on line 442. If that means anything to anyone, please let me know.