have you tried turning error capture off to see what error is returned?
have you tried unchecking "without dialog" from send mail to see if it's attached to the email prior to sending?
Also I would recommend trying to save it to the iOS documents folder by setting the path to "attachment.pdf". You can make this iOS specific by using the if ( left ( get(systemPlatform) ; 2 ) = "GO" ) catch.
I would recommend reading through the iOS development guide as well:
Now it's working, after turning error capture off I come to know that the current user don't have the acees privileges.
After login with Admin account it's working.