@Lady Serena, I'd have to say to run the server and client both on the same machine then. I do, it only causes a bit more lag for your client while you're on the server then because you're running both. It's sad to say you can't use a server on a different machine because of compression tools, but that's why I don't use them anymore.
@CaleKing, Mac is having many known issues with TekkitLite. I have no idea how to correct these as I'm a Windows connoisseur. There are some Mac pages with bugs like this, (and even the Technic Team states are are a lot of bugs with Mac clients, I would recommend using the .jar file as they stated to) so take a look at those.