greylisting filter: Unable to create regexp for ... Buffer too short

[_Lars_]

Version: 11.5.30 Ubuntu 12.04 115130819.13

/var/log/mail.err

| ... greylisting filter[7330]: Unable to create regexp for [localpart@domain]. Buffer too short
| ... greylisting filter[7330]: Unable to get data database after selection query: unknown error
| ... greylisting filter[7330]: Unable to get GL status for remote hostname.
| ... greylisting filter[7330]: Unable to check message
| ... /usr/lib/plesk-9.0/psa-pc-remote[548]: Error during 'grey' handler


$ /opt/psa/bin/grey_listing -i

| Grey listing configuration.
|
| Grey listing checking enabled
| Grey interval 5 minutes
| Expire interval 51840 minutes
| Penalty interval 2 minutes
| Penalty disabled
| Personal grey listing
| configuration allowed
|
| Server-wide black list:
|
| Server-wide white list:
| *@domain1.com
| *@domain2.de
| *@do-main3.de
| *@do-main4.com
| *@domain5.com
|
| White domains patterns list:
|
| Black domains patterns list:
|
| SUCCESS: Gathering of server wide information complete.


I have read an older post for Version 9.x, which suggests to blindly run 'mchk'. Beside greylisting the mail subsystem
is working so I don't know, what negative side effects this has.

What causes this "Buffer too short" message? Is there a way to debug this or get more detailed debug outputs?
And the subsequent message: "Unable to get data database after selection query: unknown error" What database?
Which query? A little more details would be very very helpful.

Lars