In short, your DSL provider sucks. What DSL reports does is try to ping your DSL connection to see if it gets a reply. If it doesn't it means that there is a connection failure somewhere from your house to your provider's central office. It is usually their DNS for me, but it could be something else for you.
You can switch providers, but other than that, you just live with it. When it happens, just hope it is not during a time you use it, and keep a backup dial up account for emergencies.