I have Kleopatra, but what I want to know is: when you signed the message, did you use my public key or your own public key? 
I use my private key to sign the message to you , not your public key, as it has nothing to do with this process.. You can use my public key to verify the validity of the signature and I can use your public key to encrypt a message for you, and you only by using your private key can decrypt it.
If you want, you can send me private messages to test, and I will reply to you with other messages.
Now it's clear.
Since I need your public key to decrypt this signed message, I couldn't do it because I don't have your public key.
You can post here
PGP/GPG Public Key Database: Stake Your PGP Key Here (https://bitcointalk.org/index.php?topic=1159946.0)