Issue with GnuPG -> PGP, self signature, new key

[Tony Evans]

I create a new key yesterday using gpg (GnuPG) 1.4.9 (Ubuntu 9.10),
selecting all the defaults, without changing my preferences file
first.

I exported the public key (ascii armored), no other options, and
mailed it to a contact.

They checked the key with PGP (sorry, don't know what version), and
got this output,

% pgpk -ll 'Tony Evans'
Type Bits KeyID      Created    Expires    Algorithm       Use
pub  1024 0x4250AA8D 2010-03-24 ---------- DSS             Sign & Encrypt
f20    Fingerprint20 = 73F0 396D 7EC5 0FBE CEB9  B1D0 1E90 79EB 4250 AA8D
sub  2048 0x9CCCB946 2010-03-24 ---------- Diffie-Hellman
f20    Fingerprint20 = 7B88 74DE C64A 98B1 22E8  8FE4 28EA B0A5 9CCC B946
uid  Tony Evans <email address removed>
sig      0x00000000 2010-03-24 (Unknown signator, can't be checked)

1 matching key found


The Unknown signator bit is the worrying part.  I've checked my key
with gpg and it believes it to be self-signed correctly.  Did I get
something wrong, should I have done something different on the export,
or is it just a compatibility issue with PGP (I know, hard to comment
without knowing exactly which version).

Command> check
uid  Tony Evans <tony at darkstorm.co.uk>
sig!3        4250AA8D 2010-03-24  [self-signature]

-- 
Tony Evans
Saving trees and wasting electrons since 1993
blog -> http://perceptionistruth.com/
books -> http://www.bookthing.co.uk/
[ anything below this line wasn't written by me ]