You must have a BB data plan to use BB messenger, email, Facebook, the BB browser,and other apps requiring a data connection to RIM.
And a generic data plan is not what you need. Call the carrier and have them properly activate your device and add a BB data plan. The data plan in the US is around $30 a month.
And also, please update your profile to include your cell carrier. that is good information for us to have if and when you have a problem. What do I need a Data Plan for? - BlackBerryFAQ