No response from greylistd

Hi list
I do not know what I'm doing wrong.
On another machine greylistd is running fine.
With exactly the same configuration on a upgraded etch machine,
it  doesn't work.
I tested, that the condition in exim4 configuration always returns true
so that the mail won't be deferred.
Here is the resonsible sniplet of the configuration file.
    condition      = ${readsocket{/var/run/greylistd/socket}\
                                 {--grey \
                                  $sender_host_address \
                                  $sender_address \
                                  $local_part@$domain}\
                                 {5s}{}{false}}
When I comment this out of the exim4 configuration file, the mail (of
course every mail) will be deferred as assumed.


I also recognized that the triplets file was initially missing as long I
created it and adapted file attributes.
Despite, greylist seems to lack response from the socket:
# greylist list

(No response from greylistd)
#

I checked correctness of all paths.
* binary
* socket

Everywhere the same and the socket file exists while greylistd is running.

Don't know where to investigate anymore.
Could someone give me a hint please.

Cheers Alex