If I understand the situation right, it the problem you are running into is how to pass the exception information back to the GUI since the error happens in a repository.
One way I am getting information out of the repository is through session variables.
Inside the repository you can write to the session by using:
HttpContext.Current.Session[SESSION_KEY] = ***your stuff here****;
Put your error message, or whatever information you need, into the session. In the module, you can check for the existence of the variable in the session. If there is something, you know you should print it.