Ok Endless, you get your way. I'm going to give this one more go. I'm the one that started the "So close yet so far away" thread:
http://www.rokulabs.com/forums/viewtopic.php?t=4887
I tried setting up a swap file and ran MPlay off my CF card rather than over the network (I was sure I'd setup the swap file but I hadn't).
I watched the first movie from start to finish last night without it skipping. However about 3 minutes into it the audio/video was totally out of sync so I had to skip back to fix it - then it was fine.
Gonna be watching all 6 Star Wars films over the next 2 days - will try all of them through the Roku (even though I have the DVD's) as a test...
Ross