There are several things that you can do to fix this problem. The most important thing is to update your Java. This is used by Vuze, and it can generate this kind of errors. To download the latest update, visit the official website. After you did this, update Vuze version to the latest one. To do this, open the program > Help > Search for updates. After you did this, try again to search or download anything. This solution worked for most users, but if you still can't fix the problem, contact the developer for additional support on the official website.