In general, the wiki for dogtag-2.0 seems a bit off. CurHP does not work (though HP does). SmartHP gives a syntax error, as well, but it *seems* like HP includes that functionality.
Thing is, it's not dogtag-2.0. At 2.4, when he had to upgrade some things anyway, ckknight (pitbull, cowtip,and dogtag author) upgraded everything to use dogtag-3.0 instead of 2.0, and there's no wiki for 3.0 yet.