Sophos Update Error

[Richard Sidlin]

I have installed the December Sophos file but get the following error
when it tries to update the IDE's:

 End-of-central-directory signature not found.  Either this file is not
  a zipfile, or it constitutes one disk of a multi-part archive.  In the
  latter case the central directory and zipfile comment will be found on
  the last disk(s) of this archive.
unzip:  cannot find zipfile directory in one of 377_ides.zip or
        377_ides.zip.zip, and cannot find 377_ides.zip.ZIP, period.
Unzipping the new Sophos IDE files failed. This may well be because your
Sophos installation is too old. Please install the latest release of
SophosUnzip failed with error return 9
, Bad file descriptor at /usr/lib/MailScanner/sophos-autoupdate line 94.
Done.

What's the problem please?


Richard