I have no ideas, if you reinstalled the entire game I can't imagine why you'd be missing stuff.
If you just want to add one or two techs to it, that is much easier btw. Just create the tech defs (see Techs_Amarian.xml) in a mod file, and then create a new tech tree ( see TechTree_Amarian.xml) and then apply it to the right raceconfigs (see <TechTree>TechTree_Amarian</TechTree> in CoreRaceConfigs.xml)
As long as you change nothing in the installation directory, you do not need -localdataonly