The issue will be the value you set in the Default Binding property of the fields. All of them might have the same name with the same Default Binding property value set.
May be f they are not related, provide each field a unique name.
or
Change Default Binding for those fields to None if you do not want to bind it to an XML tag.
If you still have issues, you can post your form so I can have a look at it.
Thanks
Srini