Did you initially install DNN on the localhost server and moved the installation to your dev sever and/or new virtual directory? If so you probably need to add your access url to the portalalias table in your database. You can do this manually or log onto your installation as host then go to the admin-->site settings menu, In this table there is a list of possible access urls and if the one you're calling isn't listed it will redirect you to the one on the top of the list.

Good luck,

Mike