[THIN] Error installing XenApp 5 on W2008

I'm attempting to install XenApp5 x64 Enterprise Edition on Windows 2008 x64.  Running through autorun.exe the installation of XenApp Server errors with MSI Error 1722. 

When I create a log file using this command line - msiexec /i MPS.msi /qb- /l*v C:\mps.log CTX_MF_SERVER_TYPE="E"  The tail of the log is below.

MSI (s) (30:10) [08:53:55:113]: Note: 1: 1708
MSI (s) (30:10) [08:53:55:113]: Product: Citrix XenApp 5.0 -- Installation operation failed.

MSI (s) (30:10) [08:53:55:113]: Windows Installer installed the product. Product Name: Citrix XenApp 5.0. Product Version: 5.0.0.0. Product Language: 1033. Installation success or error status: 1603.

MSI (s) (30:10) [08:53:55:129]: Cleaning up uninstalled install packages, if any exist
MSI (s) (30:10) [08:53:55:129]: MainEngineThread is returning 1603
MSI (s) (30:04) [08:53:55:129]: Destroying RemoteAPI object.
MSI (s) (30:E4) [08:53:55:129]: Custom Action Manager thread ending.
MSI (s) (30:04) [08:53:55:129]: RESTART MANAGER: Session closed.
MSI (s) (30:04) [08:53:55:129]: No System Restore sequence number for this installation.
=== Logging stopped: 11/13/2008  8:53:55 ===
MSI (c) (9C:0C) [08:53:55:160]: Decrementing counter to disable shutdown. If counter >= 0, shutdown will be denied.  Counter after decrement: -1
MSI (c) (9C:0C) [08:53:55:160]: MainEngineThread is returning 1603
=== Verbose logging stopped: 11/13/2008  8:53:55 ===

Any ideas on resolving would be appreciated.

Thanks