The first instance of a named reference should contain all the source information. Subsequent uses of the named reference should be something such as <ref name=nameused /> with a space between the /> and the end of the name.
I am unsure if your use of a number such as 3-1 is generating the error, but have you tried enclosing those ref names in "quote" marks? That, or think of a more individual name for each, so there's no need for the number-1 number-2 etc. (Just my thoughts, anyway.)
Also, it is recommended (by Find a Grave) that the abbreviation for Find a Grave be FG, not the more common abbreviation that causes distress to some.