johlum Are you asking for help? Or just logging?
If the former, IME, you can disregard both. In fact, for the "zGeo compute failed with: error kNotFound" is a known issue:
The componentTag seems to cause no issues with me.
As a heads up, you can get away with not using zbuilder(related commands) as much and instead rely more on maya commands / traditional methods. I personally mainly only use ziva commands for retrieving data as most ziva nodes can only be accessed this way (and some other things I can't recall off the top of my head due to infrequent use of them). (Is my way of not using zbuilder and related commands the best or efficient way? I can't say, but just putting it out there)
As for the solver output dynamic creature is null error -- that I'm not sure (I think i've experienced that one even when the current frame is not the same as the zsolver.startFrame on the zsolver channelbox). Since you're just starting, I invite you to script as much as you can along the way because errors like that (that I also sometimes get, but I'm too lazy or unable to trace back, or ask about) can usually be fixed by a quick scripted rebuild.
If the latter. Oops. Do your thing ^^