I run into this with AT&T all the time, they swear the account is provisioned for BES and it is not. As others have said, your BES admin can try setting your "activation password" on the Server all day long but unless AT&T gets this right it will never work. I just looked it up in our Premier account my work plan is listed as "Blackberry Enterprise unlimted add on" and it is $45/m. Now that AT&T no longer offers unlimted data it may be what pbflash stated, 2GB Enterprise package plus the $15 add on for BES.