dotted line?

Can someone tell me what this double dotted line is, and what it means, and how to get rid of it? I notice that I can’t snap the cursor to the object’s origin point.

Could be a lamp’s direction indicator (turn your lights on and off and see if the line disappears).
Also, could simply be a relationship line (shows the parenting relationships, e.g., between objects). To turn this off, in the 3D view press the ‘n’ key to toggle the properties panel, find “Display” and uncheck “Relationship Lines.”

I imagine you’re doing this, but just in case you haven’t, you can snap the 3D cursor to an object’s origin by pressing Shift+S and choosing “Cursor to Selected.” Hope something here helps!