How did I get this NullReferenceException error here right after the constructor?

Question

I\'ve had an asp.net website running live on our intranet for a couple of weeks now. I just got an email from my application_error emailer method with an unhandled exception

Answer 1

As of .NET 4.0 you can use ConcurrentDictionary and avoid the threading issues associated with manipulating the same dictionary from multiple threads simultaneously.