The code below works locally, but when I deploy it to the server it gives the following error.

Security Exception

Description: The application attempted to perform an operation not allowed by the security policy. To grant this application the required permission please contact your system administrator or change the application's trust level in the configuration file.

Exception Details: System.Security.SecurityException: Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.

The code is

protected void Page_Load(object sender, EventArgs e)
{
  DataContext context = new DataContext(Global.ConnectionString); // <-- throws the exception
  //Table<Group> _kindergartensTable = context.GetTable<Group>();

  Response.Write("ok");
}

I have set full write permissons on all files and folders on the server.

Any suggestions how to solve this problem? Thanks in advance.