After added 1000 users in Active dir by "AD Manager tool", I cannot create new mailbox manually

Hi all,

After added 1000 users in Active dir by "AD Manager tool", I cannot create new mailbox because exchange 2k10 don't have "New Mailbox" option. Besides, exchange has some problems in its structure.

Please see the pictures as follow:

Please help me solve it , I'm not experienced in Exchange server.

Thanks,

cuocdoi