InfoPath - A value in the form may be used to specify the file name. If you know the value in the form that specifies the file name, revise it and try again. Otherwise, contact the author of the form template

A value in the form may be used to specify the file name. 
If you know the value in the form that specifies the file name, revise it and try again. 
Otherwise, contact the author of the form template

As I was not using any fields in the name, I was a bit confused at first.

Turns out in my case the error message is slightly misleading and the fix is very simple.

1. Open the form in Design mode.
2. Go to the Tools menu.
3. Select manage data connections.
4. Select the dataconnection that is used to submit the form to SharePoint.
5. Click the Modify button.
6. Check Allow overwrites if file exists check box.
7. Click the Next button.
8. Click the Finish button.
9. Click the Close button.
10. Save the form.
11. Republish the form to the forms library.