I'm not familiar with this particular engine, but I'm sure that draining on a ramp is not the problem. I believe the metal ring is the drain plug gasket, this won't cause oil pressure problems, only possibly a leak if not present.
I'm sure someone that knows this particular oil filter will chime in soon. How long did you run the engine before shutting it off. It will sometimes take four or five seconds to pick up enough oil to fill the new filter and build pressure.
Hope this helps,