It seems that the Install Endpoint Protection task fails for some but not all computers.
Change: WshShell.Run <Package Name>.exe, HIDE_WINDOW, WAIT_ON_RETURN
To: sCurrPath = CreateObject("Scripting.FileSystemObject").GetAbsolutePathName(".")
WshShell.Run chr(34) + sCurrPath + "\<Package Name>.exe" + chr(34), HIDE_WINDOW, WAIT_ON_RETURN
In my case this seemed to have fixed my problem