The errors can sometimes be a result of which version of PHP you're running. Double check that, though I'm not sure what the minimum threshold Known requires at the moment. Usually these days v5.6 is a good sweet spot. Versions under 5.5 may cause errors like what you saw and I know my stupid host often defaults new installs to 5.4 for some reason.
You can also check to see if it's a known issue in the open or closed queues at the github repo: https:/
Otherwise cut/paste the error(s) into the issue queue in the repo to see what what others in the community think it could be.