Also, where at in Opera are you testing magnet links? As in, what page specifically? What happens if you type magnet://test in Opera's address field and press enter? Does that at least work?
Another thing you can try. Download the Opera installer, launch it, click "options", set "install path" to a folder on your desktop, set "install for" to "standalone installation" and install. Try in that Opera. Does it work there at least?