encryption ciphers -> Opera problem -> "Low encryption level" warning

Good afternoon, Opera complains with a warning "Low encryption level" (cf attachment). The key has a 1024 bit public part (tried with 2048 as well) and the protocol listed by openssl s_client (DHE-RSA-AES256-SHA) and by Opera (TLS v1.0 256 bit AES (512 bit DHE_RSA/SHA)) are of excellent quality as

encryption ciphers

Goot morning, Can someone please explain what the encryption cipher DHE-RSA-AES256-SHA does/means or point me to a document explaining it. Many thanks. Best Regards, Yves Kreis __ OpenSSL Project