Provider: Named Pipes Provider error: 40 Could not open a connection to SQL Server

Hi

When i tried to run the application, i got the following error as

"provider: Named Pipes Provider, error: 40 – Could not open a connection to SQL Server".

When i login to the sql server 2008, it is successfully loged in but when i tried to open the connection in my web page it leaves this error.

Can any one give me an idea about how to solve this issue.

Thanks.