There is a crash bug in the 2.0 version of Apple Remote Desktop which manifests itself when the admin account has multiple locations set-up in system preferences. The crash occurs when you fire up a scanner ... you get a couple of entries, and then whammo!, it's crash time.
The workaround is, unfortunately to remove locations from the Network panel in System Preferences. Everything works fine after that.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040914124634892