http://www.symantec.com/business/support/index?page=content&id=TECH155685
Issue
When upgrading Symantec Encryption Desktop (formerly known as PGP Desktop) to a later version you receive the following error:
Error
Environment
PGP Desktop 9.x-10.2.1mp5
Symantec Encryption Desktop 10.3.x and above
Cause
This error is caused if a user doesn’t have sufficient rights to install software on the system or if there are old PGP files in the Temp folder from a previous installation of Desktop.
Solution
Log in as the domain admin or administrator to install PGP Desktop, or contact your administrator to receive sufficient administration rights.
If you are already logged in as a user with local administrative privileges and are on Windows Vista or Windows 7, you may need to disable User Access Control (UAC) while installing PGP.
Delete all the PGP folders from the Temp folder of Windows.
For Windows XP:
Go to Start –> Run –> Type in %TEMP% This will display the contents of the Temp folder. Delete all the folders that start with PGP and then start the installation again.
For Windows 7:
Go to Start –> In the search box type in %TEMP% This will display the contents of the Temp folder. Delete all the folders that start with PGP and then start the installation again.