Agent install fails with result code 1084 - can't register runasuserlibrary.dll

I'm using LANDesk 9 with SP2. I'm trying to push push agent install to 20 Windows 7 Enterprise 64-bit workstations. The workstations are new and are identical (OS installed, joined to the domain, GPO updated, no Antivirus software installed). The install fails on four of them with the message "The agent setup program ran successfully." result code 1084. I checked the installation log on the failed workstations and it looks like the agent install fails to register runasuserlibrary.dll.

Below is the excerpt from wscfg32.xlg on one of the machines:

12/03/2011 00:04:33.847    3088    1376    tokens.cpp    562    Starting process: C:\Windows\system32\regsvr32.exe /s "C:\Program Files (x86)\LANDesk\LDClient\runasuserlibrary.dll"
12/03/2011 00:04:33.894    3088    1376    tokens.cpp    596    Processes returned : 5
12/03/2011 00:04:33.894    3088    1376    tokens.cpp    484    CheckProcessExitCode processed app name: regsvr32.exe
12/03/2011 00:04:33.894    3088    1376    tokens.cpp    616    FAILED:  Running application: C:\Windows\system32\regsvr32.exe /s "C:\Program Files (x86)\LANDesk\LDClient\runasuserlibrary.dll"
12/03/2011 00:04:33.894    3088    1376    ntstacfgDlg.cpp    1553    FAILED:  bCriticalError set to TRUE. Processing C:\Windows\system32\regsvr32.exe

I went to the machine and tried to execute regsvr32 command manually from the elevated command prompt (Run As Administrator). The error was:

Any thoughts why this is happening on some of the workstations and not the others?

Thanks.