Web Service Tutorial Errors

Hi, I’ve been doing this tutorial found here http://www.kirupa.com/flash/connecting_web_service_pg1.htm

and it’s giving me the following errors:
1046: Type was not found or was not a compile-time constant: LoadEvent.
1046: Type was not found or was not a compile-time constant: FaultEvent.
1046: Type was not found or was not a compile-time constant: ResultEvent.

I linked it to the Flash Builder library like the tutorial said to do, and it gives me those errors. What did I do wrong?