[Dovecot] Sieve extprograms problem (broken pipe)

[Ron Guerin]

I've been trying to pipe a message to an external script, and
simplifying it as much as possible, I still get a broken pipe error.

Can anyone point me in the right direction?

X-Sieve: Pigeonhole Sieve 0.3.1

Using this script for debugging:
--------------------------------
#!/bin/bash
cat > /dev/null
exit 0

server log contains:
--------------------
Apr 21 19:45:18 generator dovecot: script: Error: write(response)
failed: Broken pipe
Apr 21 19:45:18 generator dovecot: lda(support at example.com): Error:
sieve: execution of script /vmail/example.com/support//.dovecot.
sieve failed, but implicit keep was successful (user logfile
/vmail/example.com/support//.dovecot.sieve.log may reveal additional
details)

The logfile contains:
---------------------
sieve: info: started log at Apr 21 20:13:50.
error: msgid=<20140422001349.EA94C2A0CFD2 at generator.vnetworx.net>: pipe
action: failed to pipe message to program `sieve-pipe-supportticket':
refer to server log for more information. [2014-04-21 20:13:50].

- Ron