It has to do with permissions. See this Message #949387 ... it might shed some light on the subject.

~~Bonnie



>>Probably from windows app you're actually using windows authentication
>>(recommended) and not SQL authentication. Does that windows app connect if >you do that from a nontrusted computer?
>>Cetin
>
>I'm running them on the same computer. In fact they are using the same class for establishing the connection to the database and the same file for storing the connection string, so I can't imagine any way the windows app would be using a different connection. I checked the string just before issuing the open connection and it is identical in each application.
>
>It seems to me as if the web app can't even see the server. Unfortunately I'm rather a novice when it comes to IIS.