Remote Management - Rights Authentication Failed

Since upgrading from zenworks 10 to zenworks 11 I am getting the following error when I try to remote to workstations. I am not receiving this on all workstations, just some.
Zenworks Remote Management
Rights Authentication failed. An internal error occured while validating
information about the managed device. If the problem persists, contact
Novell Technical Services.

I cannot find any info on this particular error. Workstations are Windows XP SP3. This error did not occur before the upgrade to Zen 11.
Any suggestions would be appreciated.

Thank You
Debra