(It looks to me [in OS X 10.6.8] like the file to which the article directs you, /System/Library/CoreServices/RemoteManagement/ARDAgent doesn't even exist any more, having long since been changed to System/Library/CoreServices/RemoteManagement/ARDAgent.app.)
It's a moot point, given the obsolete nature of the threat, but I think the Macworld article was a little sloppy. It's
ARDAgent.app on both my 10.4 and 10.5 volumes.
