WTF Your namespace must be unique for your plugin. You must make it such that it is very unlikely for other plugins to have the same namespace. For example, if your plugin has a remarkably unique name, use it as the namespace, or otherwise, also put your name in front of the plugin name, such as sofe\libasynql for me. Main is a very generic name. If every plugin calls itself "Main", you can never load two of these plugins on the server together.
Not related to the problem mentioned in this thread, but that is something essential. Every plugin must have a representing namespace that is used to identify your plugin.