I have a program that has hand written database connections and
DataGridView that connects to my database on sql server
using computer's name .this works fine locally BUT problem occures
when running my app on local area network
causes this exception
  " Application attempted to perform an operation not allowed by the
    security policy. to grant this application the required
permission,
    contact your system administrator, or use the Microsoft .net
framework
    configuration tool
     ...
    Request for the permission of type
    system.Data.SqlClient."
I tried to granting permission using Microsoft .net configuration
tool on control panel
I set full trust for local interanet and then  unchecking  publisher
policy for some key assemblies including
System.Data

I set my application's security to full trust on visual studio env and
this also has no effect
so anyone can help me to connect my sql server through my application
on local area network .
any suggest appreciated

I use "Visual studio 2008" and "Sql server 2005 professional edition "
thanks