[exim] exim Zip module failure error

hello,
from two days this message is present in the exim log file:

2005-07-13 14:13:34 1Dsg7F-0006Os-BX malware acl condition: clamd: ClamAV return
ed /var/spool/exim/scan/1Dsg7F-0006Os-BX/1Dsg7F-0006Os-BX-00004: Zip module fail
ure ERROR
The exim configure was not modify from many day and now I have update the clamd
daemon, but the result is the same.
Best regards.

Silvano Malaguti.