zk_keys.lua goes in 'Documents\My Games\Spring\LuaUI\Configs' by default so check that you are overriding the right one. It has a date entry at the top which may be used to override old setting, however, mine says 20130630 so it looks like we haven't activated it in a while. Pastebin the uikeys.txt and zk_keys.lua that you tried to turn it into.
It might also be best to reistall a really old install. You can copy springsettings.cfg as well as zk_data, zk_order, ctrlpanel.txt and lups.cfg to keep your settings (apart from keybinds).