I'm using version 11.1 - perchance an upgrade will sort it out?
Also uninstall followed by re-install could also sort it.
You could also check the Opera forums
here to see if anyone else has this issue.
Older versions used to have this problem but I have had no problems with v11.
Firefox 4 is as close to Opera as I've found, someday I'll have the best of all worlds!