"Opera menu → Settings → Sites (in the side bar) → in Plug-ins set them to "Run automatically" and check the list in the Manage exceptions button."
I have done just this, as well as reinstalled/re-enabled flash and yet I STILL get asked to run it by clicking. Some sites bug so that even though they show the gray arrow to enable AFP, it won't do anything. It's super annoying! Any ideas on how to fix this?