You can not login to the forums from the Classified page and you cannot login into Agtalkplus from the forums.  They are 2 totally seperate systems with their own registrations and logins.  If you want to post a classified you will have to register on AgTalkplus and login from there.  If you want to post in the forums you must login from the forums.  They are two totally seperate sites just a Google and Yahoo are seperate.  You cannot login in Google from Yahoo and you cannot login to Yahoo from Google.