Algorithm 11 not available

[Graham Murray]

I am no longer able to verify signatures, or even list my keyring. I
suspect that a key as been (automatically) imported which uses SHA224
which gpg does not support. Can anyone advise what I can do to a) Fix
the keyring and b) Stop it getting borked in future?

gpg --version
gpg (GnuPG) 2.0.3
Copyright (C) 2007 Free Software Foundation, Inc.
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions. See the file COPYING for details.

Home: ~/.gnupg
Supported algorithms:
Pubkey: RSA, ELG, DSA, ELG
Cipher: 3DES, CAST5, BLOWFISH, AES, AES192, AES256, TWOFISH
Hash: MD5, SHA1, RIPEMD160, TIGER192, SHA256, SHA384, SHA512
Compression: Uncompressed, ZIP, ZLIB, BZIP2


gpg -v -v --list-keys
gpg: using PGP trust model
gpg: key 34309C41: accepted as trusted key
gpg: key E6FFC9A9: accepted as trusted key
gpg: checking the trustdb
gpg: 59 keys cached (2134 signatures)
gpg: 8 keys processed (3 validity counts cleared)
gpg: removing stale lockfile (created by 20121)
gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
:signature packet: algo 17, keyid B222F1DC7BCDCE07
        version 4, created 1158698871, md5len 0, sigclass 19
        digest algo 2, begin of digest 27 53
        hashed subpkt 2 len 4 (sig created 2006-09-19)
        subpkt 16 len 8 (issuer key ID B222F1DC7BCDCE07)
        data: [159 bits]
        data: [154 bits]
:signature packet: algo 1, keyid 7398AF7F55831030
        version 4, created 1153162490, md5len 0, sigclass 19
        digest algo 2, begin of digest 5b a7
        hashed subpkt 2 len 4 (sig created 2006-07-17)
        subpkt 16 len 8 (issuer key ID 7398AF7F55831030)
        data: [1024 bits]
:signature packet: algo 1, keyid 8CBBBC01287D010B
        version 4, created 1153162849, md5len 0, sigclass 19
        digest algo 2, begin of digest c3 51
        hashed subpkt 2 len 4 (sig created 2006-07-17)
        subpkt 16 len 8 (issuer key ID 8CBBBC01287D010B)
        data: [1024 bits]
:signature packet: algo 17, keyid 7F65C1CA8D02BBB3
        version 4, created 1174408405, md5len 0, sigclass 19
        digest algo 11, begin of digest 18 78
        hashed subpkt 2 len 4 (sig created 2007-03-20)
        subpkt 16 len 8 (issuer key ID 7F65C1CA8D02BBB3)
        data: [223 bits]
        data: [223 bits]
DBG: md_enable: algorithm 11 not available
gpg: Ohhhh jeeee: ... this is a bug (sig-check.c:450:check_backsig)
Aborted