decrypting a message.

[cronos]

Hi, 

I'm at a bit of a loss decrypting a message. No matter what I do I
always seem to get:

gpg: encrypted with ELG-E key, ID C8A0C2BB
gpg: decryption failed: secret key not available

when I run gpg like this:
$gpg --list-packets  msg.pgp
:pubkey enc packet: version 3, algo 16, keyid 9C53A76FC8A0C2BB
        data: [1023 bits]
        data: [1023 bits]
:encrypted data packet:
        length: 149
        mdc_method: 2
gpg: encrypted with ELG-E key, ID C8A0C2BB
gpg: decryption failed: secret key not available

Shouldn't it be asking me for the passphrase at some point?

Thanks