ProRes 422 support in ffmpeg (which is the fallback decoder) is still really shaky. It's particularly complicated because in addition to the decoding it then needs to be converted from a 10bit planar format to an 8bit one (causing banding problems and other such horrors).
Unless version 1.0.2 helps (it might, I did update ffmpeg at one point), I don't think that codec will work yet so you'd need to either re-export in a different format or use a different compression tool.
Re: Another update
Date: 2012-06-02 07:48 pm (UTC)ProRes 422 support in ffmpeg (which is the fallback decoder) is still really shaky. It's particularly complicated because in addition to the decoding it then needs to be converted from a 10bit planar format to an 8bit one (causing banding problems and other such horrors).
Unless version 1.0.2 helps (it might, I did update ffmpeg at one point), I don't think that codec will work yet so you'd need to either re-export in a different format or use a different compression tool.