Error: "The remote computer is not in your scope"

When trying to remote control a machine from a remote console, I get the error "The remote computer is not in your scope."  My account is a member of "Default All Machines Scope", so that shouldn't be a problem.

I found this http://community.landesk.com/support/docs/DOC-1139 and it states the target computer is set to certificate based remote control.  First off, what is that?  Second, how to I make it so it's the same as all my other computers if it's different?  Third, how do I check what all my computers are set to?

Thanks,

Chris