Plugin folder vs plugin name

[jan64]

	if cPluginManager:Get():IsPluginLoaded("Core") then
		cPluginManager:DoWithPlugin("Core",
			function (PluginHandle)
				if PluginHandle:GetVersion() >= 15 then
					if cPluginManager:CallPlugin("Core", "AddWebChatCallback", "IRChat", "OnWebChat") == true then
						HookedIntoCore = true
						LOG("[IRChat] Hooked into Core")
					else 
						HookingError("Core", 1, "CallPlugin didn\'t return true", "Web endpoint will be unavialable")
					end
				else
					HookingError("Core", 2, "Your Core is outdated, the minimum version is 15", "Web endpoint will be unavialable")
				end
			end
		)
	else
		HookingError("Core", 3, "Core not found", "Web endpoint will be unavialable")
	end

This doesn't really work. (I'm using for each plugin as a workaround atm)

Code:

[13:08:24] LUA: Plugins/IRChat/Hooks.lua:10: attempt to call method 'DoWithPlugin' (a nil value)
[13:08:24] Stack trace:
[13:08:24]   Plugins/IRChat/Hooks.lua(10): (no name)
[13:08:24] Stack trace end
[13:08:24] Error in plugin IRChat calling function <callback>()