i am sending an email from navision 2013 r2, its give me error
Surely sounds like a permission problem, the the user (client or service user).
Try to run it with the debugger and see exactly where in the code you get the problem.
Yes.i have solved the problem using the debugger, it was an permission issue of D drive.
Normally NAV Service account has full rights so if its getting executed bu that ID you wont get this error but if its getting executed from different ID then you need to provide permission manually to all those file folders.