I managed to get the Harmony Remote to work by not plugging it in until Parallels was booted (I had to restart XP to get past the "in use" message). However, the update was error prone - sometimes causing XP to blue screen with a USB error. I had to use Boot Camp in the end as otherwise it just screwed up the Harmony remote.
As to why you'd want to do this - there is no version of the Logitech software that currently works under OS X with an Intel Mac (although I understand that Logitech are working on it and I've heard that some beta versions have been spotted).
Although, there seems to be an updated version at:
http://members.harmonyremote.com/EasyZapper/Help/Help_Topic.asp?HelpTopic=WhatsNew
Last edited: May 30, 2006