While testing Flash 10 installation success, I remembered having problems with Flash on Opera. It constantly showed some grey boxes and teiling me to "click to activate" which didn't work at all.
Canonical offers a special "partner repository", which contains Opera 9.27. Unfortunately, Opera seems to have some issues with Ubuntu's Flash version (and any newer one, too).
The solution is quite simple: Just update to Opera 2.50b2.
