invalid packet (corrupt file?)

[kage at vego.no]

I'm trying to decrypt a symmetrically encrypted file, but get the following
error message(s):

C:\gpg\gpg>gpg -v -o c:\out.bkf -d d:\data.bkf.gpg
gpg: CAST5 encrypted data
gpg: encrypted with 1 passphrase
gpg: original file name='data.bkf'
gpg: [don't know]: invalid packet (ctb=63)
gpg: [don't know]: invalid packet (ctb=66)
gpg: WARNING: message was not integrity protected
gpg: [don't know]: invalid packet (ctb=37)

The outfile is written, but only partially.

Does this simply mean that the .gpg file is corrupt and that the archive can not
be recovered? It has been burned on a dvdrom, and I had some issues getting a
3GB+ file burned.

This is gnupg 1.4.0 running on Windows XP

The error messages aren't all that informative, not even in verbose mode.

Thanks for all help!

KG