What Could Cause System Apps to Run that Are Not Used
You might want to use some package inspector like e.g. App Detective to see what receivers the app in question has set up. Most likely it's acting on some broadcast, such as e.g. "sdcard mounted", to check for media, or "network changed" to check for other DLNA services.

If your device is rooted, you might be interested in apps like ROM Toolbox or Autorun Manager, which allow you to disable selected receivers, or even freeze the entire app. Without root, you can try whether that app can be disabled in Settings → Apps. It's either running for nothing or (these days it's no longer called "paranoia") working for somebody else, if you don't use it yourself.