You mean Balmung the sword of Norse mythology? Where on earth did you get the impression it was Latin? Norsemen spoke not Latin but, unsurprisingly, Norse.
You can certainly name your child Balmung, or Excaliber for that matter, but they were never personal names and thus don't belong on a database of this kind until/unless they're widely used as such.
As for the meaning, well, delve into Norse myth a bit. I've seen it listed as 'sunbeam' which seems plausible - one of the meanings of bal is 'fire'. Nothing to do with 'sword of heaven' though - a bit obvious for old myth don't you think? ;o)