If you are accessing a Mysql database then check that the access priviledges are in place for non-localhost on the database. Mysql handles localhost and "other" hosts seperatly.

If you are accessing postgress then the database server needs to be configured to allow the requesting server to access it (in the main config files). You also need to add the database user on the server with the createuser command

If you're trying to access a different type of database you are going to have to give us some more info. In fact it would be worth giving as mutch information as you can in future.

HTH

---If it doesn't fit use a bigger hammer