You can use TC with a normal OpenVPN install. Can you try to install 2.1_RC4 from the OpenVPN website and connect with that?
You just need to put the TC config and ca.cert in OpenVPN's config directory. Then connect from OpenVPNGUI.
Thanks wraithdu:I installed OpenDNS 2.1_RC4 and moved the TC config and .cert files into the config directory as you suggested. Unfortunately, I continue to get AUTH_FAIL messages - not much different than when I was using the Comodo TC client.
I am starting to think my credentials are being rejected when I attempt to login to the server. I going to try to create a new Comodo TC account, and see if that works.