When I run the example on page 202, without selecting a radio button, it produces an error: System.NullReferenceException :(

The page says taht in this case, no message at all is displayed. How can I trap the error, which I'm assuming is from trying to read: Destination.SelectedItem.Value?

Well I have no book to know everything, but I guess u r using [u]SelectedValue or SelectedIndex</u> of ur RadioButton. thats why when u havent select any it gives error!
check it & do ur task in a if

HTH.

Always:),
Hovik Melkomian.

If you want to catch it, just use a try catch block:

try

catch objNullEx as System.NullReferenceException
..
catch objEx as System.Exception

end try

Brian