Need help with Error Messages

I have a "Create Account" web form, and am looking for a better way to handle (non-validation) error-messages.

When the form is submitted, I process the form and assign various "outcome codes" (e.g. 61='Insert Succeeded') to a session variable, and then redirect to an "Outcome Page" where I use a switch statement to display the appropriate message.

How do you handle error codes/message?

Any suggestions to create a more sophisticated approach?

Thanks,