Given that the failure is occuring during a PerformCertificateDistribution() call, it could be that this is a function of being able to access those clients via RPC/WMI, which is required for Patch Manager to push a certificate into the cert store of a remote system.
However, I'm also noticing the "Object reference not set..." message, which is not the exception I would expect to see if the client connection has failed. Typically that exception is thrown as a result of something internal to the Patch Manager server.
I've sent an internal communication to our sales engineering group to have them contact you and offer assistance on this matter, but feel free to send an email to your sales rep and ask them to have the SE contact you. This is definitely not expected behavior with this wizard. The intent of the wizard is that it actually does all happen automagically. :-)
i have the same problem with the actual version from PM in the evaluation ... is there a solution already ?