There are a number of problems that can be the cause of libraries not being found. However, if everything seems to be in place and your libraries are not found, you may be facing the following problem:
Our servers are configured to allow the deployment of multiple java applications on your account. Thus, each subdirectory of your account is considered as a separate application.
If you place a page at the address http://www.mondomaine.ch/calendrier/index.jsp, this page will be considered aspart of the"calendar"application and the libraries will be searched by Tomcat inside this application. So you have to place your external libraries in :
andnot in the directory/public_html/WEB-INF/...