I just want to thank everyone for their help. Finally i've got the client working.
The reason for my Problems with the client is maybe worth a note.
I'd started again to build the client myself as i run into Problems with the distributed binary from dfryer wich kept crashing with
"pure virtual function called." What i got from the CS Forums was, that this is maybe caused by an unclean build. As there were others using this client without Problems, i'd rather supected an unclean environment on my side, so i wanted to build the client myself, so that i may could debug what's going wrong. After applying Bereror's fix for the CS compile error, i was able to build the whole thing, and ended up again with the same "pure virtual funtion called" error.
So i did again ktrace/kdump, and noticed an call to a library in /usr/local/lib/crystalspace. As i was pretty sure that this can't be right, i've checked the Directory and found a crystalspace installatioin which was about one year old. No Idea hoe it has got there in the first place. After i've deleted this ancient files, not only my build started to work, also i was able to run the binary from dfryer.

So, what did we learn from this? I have no Idea.
regards
backeroo