Yes Sir, gmx.net is an jabber-server. gmx is a doughter from the 1&1 United Internet Company. I can log on from iChat to the gmx.net server with my user data - but I can’t log on from the spark application.
What about some other clients like Pidgin, Psi, etc.? You should only try logging using bbb.ccc part. maybe Spark needs something else on the server part. It seems sometimes Spark has some DNS issues while looking up server names. But i can’t help much with that.