Problem with Martin Macok's + Jack Bertram scripts?

Hi There,
I hope this is an ok place to discuss this issue. If not, can someone
kindly redirect me to a more appropriate place? :) So I'm using Martin
Macok's and Jack Bertram scripts with ifile and I keep getting the
following error (produced in an email from the cron daemon). This cron job
is running something like every hour rather than every day (for testing).

Any ideas what might cause this to happen. I'd say it happens 70% of the
time. The other 30% the program runs as expected. As an interesting note,
mail still does get re-classified.

Thanks,
Brett

procmail: Program failure (255) of " $HOME/bin/ifile.relearn.message
$MATCH $FOLDER
2>/dev/null"
procmail: Error while writing to " $HOME/bin/ifile.relearn.message $MATCH
$FOLDER
2>/dev/null"
procmail: Program failure (255) of " $HOME/bin/ifile.relearn.message
$MATCH $FOLDER
2>/dev/null"
procmail: Error while writing to " $HOME/bin/ifile.relearn.message $MATCH
$FOLDER
2>/dev/null"
procmail: Program failure (255) of " $HOME/bin/ifile.relearn.message
$MATCH $FOLDER
2>/dev/null"
procmail: Error while writing to " $HOME/bin/ifile.relearn.message $MATCH
$FOLDER
2>/dev/null"
procmail: Program failure (255) of " $HOME/bin/ifile.relearn.message
$MATCH $FOLDER
2>/dev/null"