Allot of crawl errors in google webmaster tool

I noticed that i have allot of error in google webmaster tools.

The situation is like this:

Not found ‎(8,042)‎
Restricted by robots.txt ‎(100,000)‎
Soft 404s ‎(1)
Unreachable ‎(576)‎

Allot of Not Found is threads that we deleted. What do i need to with thoose pages? Redirect or 404 page?
I have 404 pages created on portal http://www.croportal.net/example_404 and in google webamsters tools find allot of pages that are redirected to this page? Can someone explain is this a good thing or bad and what do i need to do with threads on forum that no longer exist.
Second problem is with meta description and title tags. See attachments.

Thanks

Things that do not exist SHOULD 404.
Make sure you aren't including showpost urls in your sitemap and that you have langid set up as an elcude param in webmaster tools.
Duplicate url with ?langid=1

i dont have showpost urls

and also i have langid in webmasters tools enabled? thats strange...


thanks brian