I personally think that all trade threads and forums should be English with out exception. You don't have to be a language freak (like me) to make simple trades.
Actually there's a discussion on other boards why people don't join your community. Guess what ... it's the language.
Believe it or not, this forum will never succeed as the great european pvp center you are aiming for. Get rid of the polish aftertaste, make one single small polish language forum for your national scene and tell your members to talk english in the english forums. ALSO REMOVE ALL DUPLICATED BOARDS AMONG YOUR LANGUAGE SECTIONS, we dont need 4 general forums in english, german, polish and czech section.
AND OMG, which retarded guy is responsible for the awfully divisioned sections at this board? You'll have to learn much, if you ever want to succeed with this project. Start by examining other successfull boards and how they division their sub-forums.
Pretty disappointed with what you have done, thought you're a team with experience. Doesn't seem so. Sorry to wake you up.