Connectivity problem with SQL Server 2000

[avixorld]

Hi,
My application has accessing data from a remote database server .
My connection string is defined in web.config as follows
<appSettings>
<add key="ConnectionString" value="data source=DEVSVR;initial catalog=DEInsdata;user id=sa;"></add>
</appSettings>
Whenever I am running the application from VS.NET 2005 it runs fine but when I run application from IE the application never run and there is a message sql server 2005 does not allow remote connections and the most surprising thing is that my database is SQl SERVER 2000 so I am really confused with this error message.
Kindly help me