Hellow everybody

I have connection problem in Web Application with SQL Server.
I created sqlConnection, sqlDataAdapter, dataset with Designer.
I tested connection and data fill with Designer and it's okey.
But when I run the application exception is throwed on code line :

adapter.Fill(dataset)

Exception message is 'SqlException: Login failed for user 'STATION\ASPNET''

What is the problem and how to solve it ? Are there forums on SQL Server
in internet ?

Thank you