This site << url snipped >> hasn't been indexed by major search engines like google yet. it is like 3 months old i think. can anyone explain where it has gone wrong? Thank you.

Now the cynic would say the opening comment was an attempt at backlinks ;)
http://www.google.co.uk/search?q=site%3Awww.protibet.net
Reveals 71 pages indexed
So the problem must have been fixed

I didn't wanted to disclose my site at all. Anyways, yeah the discussion pages were indexed. I am concerned about the main site; it is not getting indexed for some reason.

You need to get backlinks for your homepage also check robots.txt file, there may be something wrong with it.
You have good number of backlink to your homepage from PHPBB.com (your signature) still have to get many more such quality links.

Review your contents and your keywords.. That's all i can to say for now....