net application running on win 2003 server craches

I have a .net application running on a win 2003 server and the program craches and returns the error below, any ideas of how to correct this?

Server Error in ‘/’ Application.

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Runtime Error

Description: An application error occurred on the server. The current custom error settings for this application prevent the details of the application error from being viewed remotely (for security reasons). It could, however, be viewed by browsers running on the local server machine.

Details: To enable the details of this specific error message to be viewable on remote machines, please create a tag within a “web.config” configuration file located in the root directory of the current web application. This tag should then have its “mode” attribute set to “Off”.

Notes: The current error page you are seeing can be replaced by a custom error page by modifying the “defaultRedirect” attribute of the application’s configuration tag to point to a custom error page URL.