There's some minor Opera bug which is not representable on IE or Chrome.
I don't know whether it's Opera to blame or my configuration.
1. Go to the main page and see if there are any 'Has New Messages' icon. Click it.
2. Read the new messages in the forum or mark them as read.
3. Return to the main page. I don't know whether it's just me or it is a universal situation but the forum I'd just visited still marked with the 'Has New Messages' icon.
Now, when you go to this forum again you'll see that there's nothing new. And only after you return to the main page for the second time the icon reflects that.
P.S. Oh, one other thing.
The address www.masterrussian.net either has some redirection error (gets you to the old masterrussian.net/forums ) or has been improperly configured. You need to type masterrussian.net (without www. part) to get to the forum.