Security.SecurityException while sending mail with attachment on my hosting server

Question

hi friends,

         I am using .Net framework 3.5 and Microsoft VS 2008,

here's the scenario:

  Am sending mail with attachment from my hosting server, I get securityexception error.  but app works fine on my local machine but whenever I try to run it from my hosting server, I get following errors:

---------------------------------------------------------------------------------------------------------------------------------------------------------
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.

----------------------------------------------------------------------------------------------------------------------------------------------------------


Here my code:

                         MailMessage objEmail = new MailMessage();

                        objEmail.To.Add(txtemail.Text.ToString());

                        objEmail.From = new MailAddress("[email protected]");

                        objEmail.Subject = "User Account Details";

                        objEmail.Body ="Your User Account was created as a " ;

                        objEmail.Priority = System.Net.Mail.MailPriority.High;

                        objEmail.IsBodyHtml = true;

                       string strFileName = FileUpload1.PostedFile.FileName;

                       Attachment attFilename = new Attachment(strFileName);

                       objEmail.Attachments.Add(attFilename);
                    
                      SmtpClient smtpclient = new SmtpClient();
 
                      smtpclient.Send(objEmail);


For uploading purpose am using "FileUplaod control" and SMTP Server mention in webconfig.

Please Help me, Thanks in Advance

Regards,

Tekk