I'm using booth Sesame .wars in Tomcat 7 on OS X 10.8, but now it doesn't work any more. I set up a new Tomcat with two new Sesame .war but now it uses the old repository. Where are these stored? (Couldn't add a new Repo or delete the old one).
Sesame Server by default stores its configuration data and database files in %APPDATA%\Aduna on Windows, $HOME/.aduna on Linux, and $HOME/Library/Application Support/Aduna on Mac OS X. If you want a completely new install, simply delete this directory. See the Sesame manual for more info.
Update you can check where your Sesame server installation stores its data by going to
http://localhost:8080/openrdf-sesame/home/overview.view
in your browser, and clicking "System" in the navigation menu on the left hand side. It shows you various configuration settings, including the data directory.