Hi Chris, maybe I do not understand your issue correctly. As it is an openhab library it “is there” without installation. The import statement tells openhab to load it as part of loading the rule file during initialisation.
I did a quick installation of the current openhab version (2.5.4-1) on my desktop and tried to follow the example I pointed out. The TR064 binding throws errors when the phone rings, but I did not see any issues when the rule file was loaded, meaning the import statement worked (although it should be pointed out that loading .* libraries is deprecated).