Would you tell me what kind of error message are you getting? Would you mind share your form with me?
You can share your form with me by doing the following:
1. Click on “Design tab” on the top left corner.
2. Click on the “Share” icon on the bottom left corner.
3. Click on “Add Collaborator” on the popup menu.
4. Enter firstname.lastname@example.org under “People to share with”.
5. In the Message edit box, type "save my form as a PDF"
6. Click the “Share” button on the bottom right of the dialog.