hmm... looks like my bad. i tracked the problem down to MPEGsource rather than MPEG2source. looks like there's some oddness in the repeat-field flag handling, causing chaotically reversed fields.
everything works fine using DGdecode. (pity, because every little bit of speed is useful to me, so the very small decoding speed difference of nic's mod was useful to me).
here's the sample anyway, if you want it - it contains some good testing material besides the field-order oddness that turned out not to be a bug in your plugin (sorry... but i'll let nic know about this).
http://210.49.108.136:8080/lain_intro.m2v