RSA Encryption / exchange with PGP

[David Hill]

We are trying to exchange files with a company using PGP Command Line - Freeware version 6.5 with RSA keys generated with version 2.6.2, file exchange remains compatible with the old 2.6.2 version. We cannot decrypt their files and they cannot decrypt ours. We could easily generate a new key, but our trading partner is very established and will not want to regenerate.

We are using GnuPG 1.2.4 to generate keys with the following options
Type: DSA & ElGamal (the only option that allowed encryption, RSA was only for signatures)
key length: 1024 bit
key does not expire
Real Name: Iowa Student Loan Liquidity Corp.
Email: dhill at studentloan.org
Comment: iLink Dev

I am sending the trading partner a new text file encrypted with the following options:
gpg --rfc1991
--force-v3-sigs
--compress-algo 1
--recipient "THEM"
--recipient "US"
--output "readme.gpg"
-es "readme.txt"

In previous attempts I didn't use the first three commands, I am hoping these will help our trading partner decrypt, but I don't have high hopes of success. Even if by some miracle that worked, we still can't decrypt their files. Do we need to use different keys or protocols in order to interoperate? This is a sample decryption session:

C:\gnupg>gpg --verbose --decrypt "install.log.pgp"
gpg: public key is F58C3B48
gpg: using secondary key F58C3B48 instead of primary key 4D1D68AC

You need a passphrase to unlock the secret key for
user: "Iowa Student Loan Liquidity Corp. (iLink Dev) <dhill at studentloan.org>"
gpg: using secondary key F58C3B48 instead of primary key 4D1D68AC
1024-bit ELG-E key, ID F58C3B48, created 2004-04-19 (main key ID 4D1D68AC)

gpg: encrypted with 1024-bit ELG-E key, ID F58C3B48, created 2004-04-19
      "Iowa Student Loan Liquidity Corp. (iLink Dev) <dhill at studentloan.org>"
gpg: CAST5 encrypted data
gpg: block_filter 024BCB68: read error (size=7302,a->size=536874118)
gpg: WARNING: message was not integrity protected
gpg: block_filter: pending bytes!

C:\gnupg>