MacMAME is based on older versions of MAME, the last being in the 0.103 range, I believe. The Donkey Kong sound used to need samples to be complete, but as of MAME 0.116, samples were no longer required. So, it would sound like you need samples if you wish to use MacMAME - get them here: HERE. Make sure you check the OLDER SAMPLES, as they would be located in that menu.