Powerful IDEs such as Eclipse or NetBeans are useful even for dynamic languages as Ruby, which don’t need to be compiled like Java or .NET applications. They offer all necessary functionalities, syntax highlighting, and debugging possibilities. Yet they also have drawbacks, sometimes they are quite slow: Eclipse seems to be very slow at large CSS files, while NetBeans constantly tries to scan all your projects. And sometimes their behavior is difficult to understand. For example, if you get the error message “Could not connect to webserver” in a NetBeans RubyOnRails project, then you might have a faulty plugin or gem. This is possible if you just have modified or edited it. Then you have to restart the server, and this does not work if you have introduced a fatal error. If the Rails application can not be started, then NetBeans does not display the correct error message. It simply says “Could not connect to webserver”. The reason can also be a missing or faulty gem which is required for your application, for example a broken rmagick gem after an OS update of Linux. In this case, examine the log in the output window (which can be opened in NetBeans with Ctrl-4) and install the required gem.