Failed running extprograms execute via socket - fatal recv(MSG_PEEK) failed disconnected

[E.B.]

> >> I switched from running my extprograms execute script directly
> >> to running with dovecot socket. Log shows only this
> >>
> >> dovecot: lmtp(test at example.com): Debug: wdi0Tb5VPlGfPnEAM/SpMA: sieve: action execute: running program: test
> >> dovecot: lmtp(test at example.com): Debug: Namespace : Using permissions from /vmail/example.com/test: mode=0770 gid=default
> >> dovecot: script: Fatal: recv(MSG_PEEK) failed: disconnected
> >>
> >> For testing I opened up the script and socket with
> >> permissions 777 but the error seems to indicate
> >> less about permissions more about some kind of
> >> protocol problem i guessing.
> > No one can help? Is anybody using the Sieve extprograms
> > execute via Dovecot socket service? I think my config
> > is vanilla, no? All other Dovecot and Sieve things
> > (including quota service scripts configured very
> > similarly) work fine.
> >
> > Taking a look at the code, the error seems to indicate
> > that no input is available on the socket when Dovecot
> > checks. Does my script need to behave differently?
> > What exactly to do?
> >
> > Should I just go back to direct execute? What's the
> > difference anyway beside the user/permissions will
> > be different?
> >
> > Stephan? Anyone?
> 
> Last two changes should fix this:

Not yet -- this may be unrelated(?) but here is what I have
after installing the newest source package:

Error: Couldn't load required plugin /usr/local/lib/dovecot/lib90_sieve_plugin.so: 
dlopen() failed: /usr/local/lib/dovecot/lib90_sieve_plugin.so: undefined symbol: 
mail_deliver_ctx_get_log_var_expand_table

Help?