Error message I get when recording: Selected audio device has no input channels available

Not surprised it doesn't work too well with an MME driver, quite frankly - that's likely to be interrupted by anything the OS cares to throw at it. As far as I'm aware, there's an ASIO option that will serve you a lot better because the OS can't interfere with that at all. If you installed the Mackie software package, you should find it listed if you change the device class in the Audio Hardware box to ASIO. If it isn't there, check that you are using an up-to-date driver.