"create now" vobsub, leaves empty .sub file

Hi all,
great program.  using it daily.  finally moved onto my anime dvds which need
at least two language audio tracks (handles easily) and i want the original
english subtitles in vobsub.  (ie, not text subs).

my problem is that
this:
mkdir -p /home/erict/dvdrip-data/ferris/avi/001 && cp
/home/erict/dvdrip-data/ferris/tmp/ifo/vts_01_0.ifo
/home/erict/dvdrip-data/ferris/avi/001/ferris-001-sid00.ifo && cd
/home/erict/dvdrip-data/ferris/avi/001 && chmod 644 ferris-001-sid00.ifo &&
execflow cat /home/erict/dvdrip-data/ferris/tmp/ferris-001-sid00.ps1 |
dvdrip-progress -m 1 -i 1 | subtitle2vobsub  -i ferris-001-sid00.ifo  -o
ferris-001-sid00 &&sed 's/^id: /id: en/' < ferris-001-sid00.idx >
vobsub13344.tmp && mv vobsub13344.tmp ferris-001-sid00.idx

of which the critical section is:
cat /home/erict/dvdrip-data/ferris/tmp/ferris-001-sid00.ps1 |
dvdrip-progress -m 1 -i 1 | subtitle2vobsub  -i ferris-001-sid00.ifo  -o
ferris-001-sid00

leaves me with an empty sub file.   yes, there are indeed subs in the
vobsubs.

i can extract and create the vobsub by hand like this:

cat /home/erict/dvdrip-data/ferris/vob/001//* | tcextract -x ps1 -t vob -a
0x20 | subtitle2vobsub  -i ferris-001-sid00.ifo  -o ferris-001-sid00

and it works as expected.  it appears that the existing ps1 file doesn't
have the subs in it??

also, when i try to use the 0 byte .sub file, mplayer sees the vobsub but
its language is "enen"   i'm assuming from this:
sed 's/^id: /id: en/' < ferris-001-sid00.idx
?

i'm always using single rips (ie, not splitting the avi)
what am i doing wrong?

thanks!

-- 
"The plural of anecdote is not fact."