Seems some paths are different in 10.5 which breaks the script above.

The executable 'lsregister' can now be found (among other routes) via:
/System/Library/Frameworks/CoreServices.framework/Frameworks/LaunchServices.framework/Support/lsregister

I also added this line to my AppleScript:
do shell script "/bin/mv ~/Library/Preferences/com.apple.LaunchServices.plist ~/Desktop/"
...which moves the user's LaunchServices.plist to their desktop.

I hope Mark has time to stop by and approve there changes...
but I feel comfortable that they are correct.

Hmm, maybe this info should be reposted in the Leopard forum?

-HI-