Just recently I installed SharePoint cleanly and started to go through the Central Administration. I noticed that when clicking on Blocked File Types I received an Unknown Error page and saw the following line in the logs:
8dzz High Exception Type: System.NullReferenceException Exception Message: Object reference not set to an instance of an object.
It occured that maybe the Blocked File Types configuration is created on the first Web Application. I went ahead and created a Web App and then went back and the error no longer exists. Thought I would post this since I couldn't find a solution online...
