Problem in Vb

Hi Everybody,
I am using vb6 and have a problem with Dialog box . I have used Dialog box to save a file . But After i enter file name in Dialog box and run my Application than it fails to run.
i am running batch file using shell() function.
But i fails to create process and application returns to main form.
if i close my application and run it again than i run but again as soon as i write file name in dialog box it wont be able to run batch file.

Plz help …..