I can't open thread in Sell,Buy category

I posted like 50 posts already. have been a member of DF for a while and I still can't create threads in Buy, Sell category. What am I doing wrong.

Can anybody explain this to me.

Regards,

 

You also apparently can't read the rules. Try again.

http://forums.digitalpoint.com/faq.php?faq=dp_faq#faq_posting_guidelines

Hint: "a while" isn't covered there.

Also, in the future, please try to search for an answer before inadvertently posting a duplicate question that's been answered dozens of times.