This has been suggested before and it was always told to use IRC. IRC is better for it, not everyone is going to hang here with their browser window open for a half-assed chat with people.
Shout boxes always look horrible on forums. If you really want the forums to look like a place created by noobs then yes a shout box would be awesome, however if you have standards then you'll know that shout boxes are just a gimmick, work terribly and are very untidy.
use irc then you dont have that problem with catching an admin ..
But if they are not in IRC how can I asked if I have some problems
Admins are on IRC more than the forums. I can see the anonymous users and at any given time there are more admins on IRC than there are on the forums, they may not reply straight away but if they're in the user list then they will be receiving your messages.
If they are active and reply straight away then you can have an active public conservation or a private chat with them (which most shout boxes don't provide a way to do so)