When you ran the upgrade, did you see upgrade progress on the screen? If not, your upgrade may not have run. You should have seen progress messages on the screen, there should be log files, and there should be an indication in the Versions table in your database.
Also, when upgrading from 5.x, it's best to do this in steps following the suggesting upgrade path:
http://www.dnnsoftware.com/wiki/pag...grade_path So, go from 5.1.2 to 5.4.4 and then follow the steps.
It is also likely that you will find issues that require fixing along the say. So, it's best to make a copy of the site and do the upgrades on it. Then replace the current site with the upgraded site.