Problem with DS/DSS encryption and decryption

Hello ,
I am developing a application using java language. In my project i am using openPGP “Bouncy Castle Crypto API” for PGP cryptographic operations. I am using keyring file to encypt or decrypt files in my application.But If I try to use a DH/DSS keypair , I get an error message saying :

org.bouncycastle.openpgp.PGPException: unknown parameters or keysize

I am not able to PGPencryt or PGPdecrypt using DH/DSS key pair.
Does “Bouncy Castle Crypto API” support DH/DSS algorithm ?? or
Are there any other packages that supports both RSA as well as DH/DSS encryption and decrytion .

please suggest.This is a very urgent requirement.

Thanks in advance,