[Josh Beardsley]

Did you get your answers? Under system preferences/memory&cache i have found that if you crank it back to about 60-70% application and about 30% still cache it seems to work fine. It just needs some computing power to handle the other apps you have running too.
Are you shooting in PAL? if not you would want to choose something like 60i or 30f and not 50i or 25f.
Let me know what you find out about the import problem not having enough data. I am having the same issue and am chalking it up to a slow computer at this point. But as I have always found there is a solution out there. Just have to do more digging.
Thanks.
Josh.