'property cannot be listened to' error

    Oct 04 2013 | 4:56 am
    I'm getting this message in the Max window for most of the paths I send to
    My path is: live_set tracks 0 clip_slots 2 clip, so it seems like it should be pretty simple but I'm getting this message for the property "is_playing" and pretty much any boolean property. The only ones that provide any info are the function properties. However, the general "is_playing" property (as it applies to Live's master transport) does give the correct result.
    With the same path / id, live.object also provides the correct status, but I need the updates to be continuous without having to ask it for info all the time.
    Any ideas? I feel like I must be missing something here - totally stumped!