I’m not an expert here, but I believe that Parakeet is dependent on the GHPython plugin, or at any rate the ‘Discretized’ plugin that might be part of it. Do you have GHPython installed?
You might be amused by my attempt to use all the Parakeet components: Exercise in using all the Standard Grasshopper components. I was able to get Complex T A to work correctly, but it does not work if I disable Python. That said, I find the component to be a strange one, and unwieldy to configure usefully. See the ParakeetCurve.gh in the above thread.