Security Policy problem.

Hi all.. I have a vb.net program in my computer, but when I copy and paste its .exe file into a shared folder so anyone on the network can run the program I keep getting this error below:.. .."The application attempted to perform an operation not allowed by the security policy. The operation required the security exception. To grant this application the required permission please contact your system administrator or use the Microsoft .NET administrative tool.".. How do I fix this problem? Does anyone know?.. Thanks..