Yeah that's weird Fuzzy, I painted cars "part time" for years and any good acrylic laquer (from which Duplicolor is derived) will stand up to paint spills after a week of curing in reasonably warm weather. Looks like you just got a dud can.
I'm very fond of 2 pack (catalyzed polyurethane) paint, but it is deadly, full of nasty carcinogens that will kill you if you don't wear a breathing mask. For that reason alone, I don't like to recommend it to inexperienced or ill-equipped painters.
I'd suggest that when you repaint it, go to an automotive paint supplier and get one of their free "how to" sheets, it'll tell you the correct type of primer, thinner, paint and clear coat to use, remembering that "solid colors" (non-metallics) don't require clear coating. Cheers, Terry.