Thanks for the quick response on this. Plugging the flirc straight into the macbook, no USB hub.
I cleared the configuration and the forced the firmware upgrade as per instructions... This has helped, It now seems to be stable, so no more cursor jumps or random typing.
But it the flirc / software still not picking up my button presses from harmony ultimate remote, so I still can't configure. I know the macbook retina has no IR, but was hoping the flirc would provide the IR??