Which version of huffyuv did you use to originally encode the file? I think that 2.2.0 is buggy, but it will crash rather than produce garbled output. I use v2.1.1 CCESP Patch v0.25 - I don't exactly know what the patch is for.
It's also possibly a result of encoding with the wrong field threshold. Try changing the value from 240 to 480.
You could also try the ffdshow huffyuv decoder. Go into the VFW codec configuration and set the libavcodec as the decoder for huffyuv.