Symantec Endpoint Protection fails to install on Ubuntu Linux and displays error: "Missing package files"
"Missing package files... please check the package and use a valid one."
"Virus protection component failed to install"
The Symantec installer is using incorrect pathing under some versions of Ubuntu Linux. This has been fixed in Symantec Endpoint Protection 12.1 RU6.
Solution is to upgrade to Symantec Endpoint Protection 12.1 RU6. See Download the latest version of Symantec Endpoint Protection.
As a workaround copy the contents of the extracted sep-deb.zip archive to the root of the file system, and run the installer from there. That is, NOT from "/root" but from "/".