I wonder if someone had similar issues I am dealing with right now and will be able to give me a helpful hint.

I am currently using DNN4.0. I tried to upgrade to 4.3.3. I Downloaded DotNetNuke_4.3.3_Upgrade.zip and unzipped it into a temp folder. I backed up the content of my dotnetnuke folder and pasted the content of the newly downloaded folder over Website directory. Then I opened release.config and development.config and changed: connection string, machine key, validation key, and namespaces sections based on my old web.config file. I restarted IIS and deleted all temp internet files just to be safe. Then I navigated to http://localhost/dotnetnuke and was excited to see all the successful upgrade messages on my screen. I then clicked on the link to access my portal and was redirected to a custom login page. When I provide user name and psw I get 'Object reference not set to an instance of an object' message.

I tried to roll back to the prev version of DNN. It is working but each time I compile a module, site, or solution the system shows me assembly versions of a db and a DNN. Then it says that the system is being upgraded and shows me a link to navigate to my portal. My guess is some changes were made to the DNN db when I attempted to upgrade and now even though i downgraded to 4.0 still has new settings.

Any input will be appreciated.