Error: Error 1718. File was rejected by digital signature policy
When installing a large Microsoft Windows Installer (.msi) package or a large Microsoft Windows Installer patch (.msp) package on a computer that is running Microsoft Windows Server 2003 or XP, the following error message displays:
Code: Error 1718. File FileName was rejected by digital signature policy.
Similar errors may also appear stating:
"The installation of <installation location>\ArcGISServerDotNet931.msp is not permitted due to an error in software restriction policy processing. The object cannot be trusted."
"1706 The installation source for this product is not available. Verify that the source exists and that you can access it."
This happens during the installation of an ArcGIS .msp file such as service packs and the 9.3.1 update.
This problem occurs if the Windows Installer process has insufficient contiguous virtual memory to verify that the .msi package or the .msp package is correctly signed.
Solution or Workaround
A supported fix is available for Windows Server 2003.
See the Related Information below for the Microsoft Knowledge Base document as well as the Windows Server 2003 fix.
Completely exit from the ArcGIS Service Pack installation.
Download and install the Microsoft hotfix. See below for link.
Install the ArcGIS Service Pack.
Note: This error can also occur on Windows XP; however, Microsoft has not released a fix for this issue.