Video Contact Sheet on Lion from movies downloaded youtube MP4

Hi

I am running Lion with latest patches

> uname -a
Darwin wger.local 11.2.0 Darwin Kernel Version 11.2.0: Tue Aug  9 20:54:00 PDT 2011; root:xnu-1699.24.8~1/RELEASE_X86_64 x86_64

Installed mplayer, ffmpeg, gnu-getopt and ImageMagick through brew.

I am unable to generate Video Contact Sheet images from movies in MP4 downloaded off youtube.

Tried with two bash scripts. They are only front-ends for mplayer/ffmpeg.

> ./vcs-1.12.3.bash ../test.mp4
Video Contact Sheet *NIX v1.12.3, (c) 2007-2011 Toni Corvera
Unable to locate DejaVu Sans font. Falling back to helvetica.
Processing ../test.mp4...
Unable to find length of file "../test.mp4". Can't continue.
Cleaning up...
> ./slickslice-0.9 -x ../test.mp4
VERSION: SlickSlice 0.9

INFO: Looking for the programs SlickSlice depends on:
INFO: 'convert' found, 'mplayer' found, 'montage' found, 'identify' found
USER: SlickSlicing "../test.mp4"

WARN: Custom font DejaVu-Sans-Condensed was not found
WARN: Default font will be used.
HINT: run 'identify -list font' for a list of all available fonts
HINT: or install the font package with DejaVu-Sans-Condensed
INFO: Examining /Users/max/Downloads/bin/../test.mp4
INFO: regular file
sed: 1: "/^ID_/ { s/[]()|&;<>`'\ ...": extra characters at the end of p command
sed: 1: "/^ID_/ { s/[]()|&;<>`'\ ...": extra characters at the end of p command
sed: 1: "/^ID_/ { s/[]()|&;<>`'\ ...": extra characters at the end of p command
INFO: Movie image width is undefined
WARN: Is this a videofile at all?
ERROR: No video to slickslice :(

project sites:

SlickSlice
Video Contact Sheet *NIX

any idea?