Attaching a content database to a web application

HI All,

I have taken backup of a database from MOSS 2007 and i restored it into SP 2010  farm, in the sql server 2008.Then i mounted it to a web application through cmdlets "Mount-spcontentdatabase".

It was successful . But when i went to the view site collection in that particular web application, it is not opening and when i tried to create a new site collection under that web application it is showing an error.

Why is this happening, I am using SP 2010 environment.

Thanks;

Aditya