The requested domain name is not configured for any web site: http://www.medicalnet.pl/Opole--3,5-mln-zł-na-oddział-zakazny,wiadomosc,2,listopad,2010.aspx
If you're an administrator of this site, you need to go to Site Manager -> Sites and use the following domain name either in the Site properties or add a new domain alias: www.medicalnet.pl