HTC Incredible 2 clearing "App Associations" on reboot - why?
Has your friend modified the Linkify app that implements the App Associations? Typically both the Linkify app that actually performs the association and the Settings app where you set them are signed by the system signing key. If the Linkify app was replaced with a modified version not signed by the system signing key, which is possible if you unlock and root your device, I imagine it would have trouble accessing the settings.