Hello all.
We got SQL Server 2005 and client application c# and .net 2.0
After running few minutes our application disconnected with error
A transport-level error has occurred when sending the request to the server. (provider: Named Pipes Provider, error: 0 - An unexpected network error occurred.)
whats wrong

Transport-level error
qrz
Mostlikely the server closed the connection. Please check if you can run simple application, such as query a simple table "select * from table A", repeatively for a while. If you can pass that, mostlikely, your application violated some contrains on server and connection was closed . You can take a look of errorlog or profiler to troubleshoot.
Thanks,