[fetchmail]SYNTAX error from fetchmail

Hi all,

I send this to both the fetchmail and mailfilter lists as I have no clue who
the perpetrator is.

I added mailfilter to my fetchmail configuration by calling it from the very
first connection in .fetchmailrc:

        username jan(_at_)klaverstijn(_dot_)nl is * here
        password ****
        keep
        preconnect '/usr/local/bin/mailfilter'

This can work for a few hours (I fetch mail every 5 mintes) but than,
without any cause to my knowledge, I get the following in the fetchmail log:

        Query status=5 (SYNTAX)

From that point no mail is fetched for user jan. This is hard to reproduce
and debug since I just have to restart fetchmail to clear the situation.
When mailfilter is run from the command line it works flawlessly.

My .mailfilterrc file is:

        SERVER=pop.euronet.nl
        USER=jan(_at_)klaverstijn(_dot_)nl
        PASS=***
        PROTOCOL=pop3
        PORT=110

(... more accounts ...)

        VERBOSE=3

        REG_CASE=no
        NORMAL=yes
        DENY="this really worked for me"
        DENY="get rich"
        DENY=^Subject: Stock Market Volatility
        DENY=^From:(_dot_)*(_at_)freeze(_dot_)com
        DENY=^From:(_dot_)*(_at_)prontomail(_dot_)com
        DENY=^Subject:.*MAPABO nieuwsbrief*
        DENY=^To:(_dot_)*gek(_at_)klaverstijn(_dot_)nl
        DENY=^From.*stockinfoking.com
        DENY=^From.*terminations.net

        # End of file

Any ideas?

Jan Klaverstijn