The computer is not a member of this network or is an unmanaged member of the network.
The first computer to connect to the network starts out with management access. If you uninstalled from that computer, you may have lost the management keys and therefore need to start over by clearing out the old network information. You can clear out the old network information by following these steps:
1. Stop the McAfee Network Agent (start/run "net stop mcnasvc"

on all computers on your network.
2. Remove the file \Documents and Settings\All Users\Application Data\McAfee\MNA\NAData on all computers on your network.
3. Restart the McAfee Network Agent on the machine you want initially to have administrative access (start/run "net start mcnasvc"

.
4. Restart the McAfee Network Agent on the rest of the machines.
Note: Make sure that the Cx has 2 or more computers are connected to a network and has McAfee Security Center(new version) installed on each computer.
*Tnx to Jeff for the update*