Why not? What does not work? All the more odd because the obvious things are default: you have to accept (some) Cookies, but Opera does do that by default; and you have to allow redirection -- which again Opera does do by default. Still, if it does not work you can try setting options specific to the ORG (forums.totalwar.org) by right clicking and selecting “Edit Site Preferences” from the context menu. Same preferences can be set for *all* sites from Tools -> Preferences -> Advanced.