Are you sure that "app_name" exists? If it exists, are you sure it knows how to respond to AppleEvents ("AppleEvent-aware")? Try the following test - run Activity Monitor (in /Applications/Utilities ) and run this script:
tell application "Activity Monitor" quit end tell
This works fine for me - if it works fine for you, then the problem is probably related to your specific application. If this does not work for you, you have some kind of system problem - try it on another Mac to check?
Paul r
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