error installing agent on some pcs

I have about 600 pcs i've been deploying the vcenter protect agent to.  Most existing ones were done through the console, and new pcs being deployed we use the stplatformupdater.exe on to deploy it.  On probably 30 machines, I have been unable to get the agent to register itself no matter what I do.  I try through the console, and using the exe and always get one of two errors

2013-04-04T15:19:33.9851166Z 07e8 I STAgentManagement.cpp:536 'C:\Program Files (x86)\VMware\vCenter Protect Agent\STAgentManagement.exe' is starting, version: 8.0.3965.1.

2013-04-04T15:19:35.6855275Z 07e8 E STAgentManagement.cpp:695 class STServiceModel::Wws::CWebServiceException at RegistrationServiceClient.cpp:496: Unable to register the agent with the provided registration cookie.

Error detail:

The body of the received message contained a fault.

The fault reason was: 'Internal error'.

or

2013-05-01T02:54:46.0497283Z 0c14 I STAgentManagement.cpp:536 'C:\Program Files (x86)\VMware\vCenter Protect Agent\STAgentManagement.exe' is starting, version: 8.0.3965.1.
2013-05-01T02:55:20.4330099Z 0c14 E STAgentManagement.cpp:695 class STWin32::CWin32Exception at PrivateKeyInfo.cpp:164: Error 5: Access is denied.

I use shared passphrase when doing the stplatformudpater.exe and I know it works because it allows me to fetch the policy list.  It just never is able to register.  Any idea what could be wrong on these machines? It happens on both windows 7 and xp.