Student
What other kind of errors are there, apart from build errors?

Teacher
Well... hold on, let me go look at the file...
Okay, there's 2 types of errors.
First of all, there are unhandled exceptions. Those are handled by this function right here. [Points to the Application_UnhandledException() method] They're usually database-related... a file's missing that shouldn't be... login errors... it's usually the user's fault.

The other type is a Try-Catch. Those are usually login-related.

So... any other questions?