passphrase doesn't work?

[Maury Markowitz]

I'm being sent a file that's encrypted using our PK by some version of
PGP using IDEA (or course). I'd like to decrypt it using gpg, in a CMD
shell, under Windows XP.

To get started, I downloaded and installed gpg, downloaded and copied
over idea.dll, copied over our PGP keyrings and renamed them to
".gpg", used --homedir to point everything to the network folder where
I put it all, and started experimenting...

gpg --homedir o:\utilities\ --list-keys

returns a list of keys in "pubring.gpg" (should it do the same for
secring?). One of the keys in the list is the 2048-bit key that I'm
trying to use. It seems to be working so far!

Ok, let's try to open the file...

gpg --homedir o:\utilities\ --load-extension o:\utilities\idea.dll -d
o:\temp\downloaded_20080219.txt.pgp

You need a passphrase to [...]
[type in the passphrase]
gpg: Invalid passphrase; please try again ...
[repeat, making very sure]
gpg: Invalid passphrase; please try again ...

Ok, the passphrase is correct. Any ideas what's going on here?

Maury