[exim] dkim error in paniclog

Hi all,

after upgrading to exim 4.71 we get the following error in paniclog:

2009-12-02 22:06:05 1NFwOj-0005JP-2X DKIM: Error while running this message
through validation, disabling signature verification.
2009-12-03 00:36:35 1NFykN-0007Js-6B DKIM: Error while running this message
through validation, disabling signature verification.
2009-12-03 01:01:03 1NFz83-0001RP-9U DKIM: Error while running this message
through validation, disabling signature verification.

The error does only occur from time to time, the messages are delivered
anyway. Out of 9000 mails with dkim-Header, we got only 12 error messages.
DKIM is not used in any acl, this is only the default dkim validation.

As the error is logged to paniclog, I suggest I should react in someway.;-)
Can anybody give me any advice what to do?

Unfortunately, I don't have access to the headers, as the mails get delivered
to our customers.
System is debian.

--

Thanks in advance,

Kerstin