Thank you for your post.
What steps are you taking? Try opening the database file in FileMaker Go as you normally would. Then, in the upper right corner, tap the gear icon. In the Menu that displays, tap "Save / Send". In the Save / Send window, tap "Database". In the Database window, tap "Email", address the mail to the email address on your desktop machine and tap "Send" in the upper right corner.
Another option would be to physically connect your iPad to your desktop machine, launch iTunes on the desktop machine, and copy the file from FileMaker Go to your desktop machine.
Let me know if you need additional clarification.