Hey Carlos,
I added both PlasticSCMPlugin.exe's to my environment variables, then restarted my PC and it worked. For anyone else having this issue I'm not sure if it was the path or restarting that fixed it. I could not find a way to launch Unity without the Hub so I'm glad that wasn't an issue. We are still in early testing phase so if I have any other issues I will email support.
Thanks,
Ben