I get the exact same error.
I know my Global.asax work, since I use it for session_start and other events. However, I get same error as the poster above. I have not yet manageed to get this working: "Attribute 'Implements' is not a valid attribute of element 'Application'."
The error comes just by having the lines. It looks like the syntax of Implements is wrong. I have not code-behind on my global.asax file, so I can´t put the call to the elements there either..
I begin to suspect that the attached demo .cs file for global.asax is .vb.. I do not see that the commands are valid in c#.