Fianly got an info about the error logs but seems to be not very meaningful or helpful…
serverXYZ:/var/log/apache2# cat error.log | grep webdesign-in-muenster.de
[Sun Jan 02 07:41:27 2011] [client 95.108.158.233] File does not exist: /myserverpath/html/webdesign-in-muenster.de/robots.txt
[Sun Jan 02 12:20:52 2011] [client 89.244.101.196] File does not exist: /myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Mon Jan 03 08:18:21 2011] [client 174.129.228.67] File does not exist: /myserverpath/html/webdesign-in-muenster.de/robots.txt
[Mon Jan 03 08:37:42 2011] [client 95.108.158.233] File does not exist: /myserverpath/html/webdesign-in-muenster.de/robots.txt
[Mon Jan 03 11:01:24 2011] [client 89.244.122.16] File does not exist: / myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Mon Jan 03 18:28:40 2011] [client 89.244.102.76] File does not exist: / myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Mon Jan 03 21:05:06 2011] [client 89.244.122.16] File does not exist: / myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Tue Jan 04 10:43:07 2011] [client 95.108.158.233] File does not exist: /myserverpath/html/webdesign-in-muenster.de/robots.txt
[Tue Jan 04 13:05:31 2011] [client 89.244.97.97] File does not exist: myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Tue Jan 04 13:56:01 2011] [client 91.17.73.111] File does not exist: myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Tue Jan 04 13:56:24 2011] [client 91.17.73.111] File does not exist: myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Tue Jan 04 14:57:43 2011] [client 218.213.130.157] File does not exist: /myserverpath/html/webdesign-in-muenster.de/robots.txt
[Tue Jan 04 21:02:47 2011] [client 85.10.211.218] File does not exist: / myserverpath/html/webdesign-in-muenster.de/robots.txt
[Tue Jan 04 21:28:59 2011] [client 89.244.113.173] File does not exist: /myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Tue Jan 04 22:21:39 2011] [client 79.247.203.159] File does not exist: /myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Tue Jan 04 22:21:40 2011] [client 79.247.203.159] File does not exist: /myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Tue Jan 04 22:21:42 2011] [client 79.247.203.159] File does not exist: /myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Tue Jan 04 22:30:54 2011] [client 216.99.58.163] File does not exist: / myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Tue Jan 04 22:30:57 2011] [client 216.99.58.163] File does not exist: / myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Wed Jan 05 10:36:34 2011] [client 89.244.111.188] File does not exist: /myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Wed Jan 05 10:36:36 2011] [client 89.244.111.188] File does not exist: /myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Wed Jan 05 11:20:02 2011] [client 95.108.158.233] File does not exist: /myserverpath/html/webdesign-in-muenster.de/robots.txt
[Wed Jan 05 14:57:27 2011] [client 89.244.121.242] File does not exist: /myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Wed Jan 05 17:47:13 2011] [client 78.53.65.165] File does not exist: myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Wed Jan 05 17:47:13 2011] [client 78.53.65.165] File does not exist: myserverpath/html/webdesign-in-muenster.de/favicon.ico
[Wed Jan 05 17:47:16 2011] [client 78.53.65.165] File does not exist: myserverpath/html/webdesign-in-muenster.de/favicon.ico