Hi, im self-study in asp.net 2.0. im having a problem in chapter 4 in user account configuration. once i click to administer website, i reach to the page of web site administration tool, then when i click to security, i get the error message :
There is a problem with your selected data store. This can be caused by an invalid server name or credentials, or by insufficient permission. It can also be caused by the role manager feature not being enabled. Click the button below to be redirected to a page where you can choose a new data store.

The following message may help in diagnosing the problem: Unable to connect to SQL Server database.

what did i make mistake and what should i do? pls help me to continue my study. thanks a lot.