Well, I had the same problem and did the same as you except I left it in the down position for a few days. It worked great for a few days on the car and then started leaking terribly. Then when I was on a long trip, i went over 74 mph (where it raises in US cars) and noticed it didn't go up. About 5 minutes later when I slowed at a light, i could hear the motor still running. Pulled off the road to see the fluid running all over the rear bumper and deck. I had to pull out the power wire to the motor to make it stop. I have a feeling I something is going to be destroyed if and when I end up opening it. Funny thing is the dash error no longer pops up!

 

Update:

I'm having a weekend off from trying to fix my exhaust, so I thought I'd have another go at fixing the rear spoiler

Bottom Line is this:
Porsche designers are very bad at their jobs


Who at Porsche thought that hydraulic rams without seals, and microswitches would be a good idea

The person(s) that came up with this set-up are low rate designers to say the very least