The problem seems to come from the LaunchAgent plist file.
I modified mine with Lingon to set the value RunAtLoad wich wasn't present in the original one. Attached it to let you test if works for everyone (Copy it in /Library/LaunchAgents).
It seems to work here.
4/17/09 11:28:13 AM com.apple.launchctl.LoginWindow[115] launchctl: Dubious permissions on file (skipping): /Library/LaunchAgents/org.voodoo.trackpad.configurationloader.plist
4/17/09 11:28:13 AM com.apple.launchctl.Background[116] launchctl: Dubious permissions on file (skipping): /Library/LaunchAgents/org.voodoo.trackpad.configurationloader.plist
4/17/09 11:28:14 AM com.apple.launchd[1] (com.apple.UserEventAgent-LoginWindow[117]) Exited: Terminated
4/17/09 11:28:14 AM com.apple.launchctl.Aqua[122] launchctl: Dubious permissions on file (skipping): /Library/LaunchAgents/org.voodoo.trackpad.configurationloader.plist
Mine does not load, same as the original plist, pls help
(sorted that out) - since permission has to be set to read only in order to load