In the very comprehensive index of my large-scale Rheinland-Pfalz-Saarland
(sic) touring map, I found two places called Barweiler, one of which was
slightly South of Kreutznach and very likely is the place of birth of Aubrey
Jacobus's ancestor. Although it wasn't actually marked on this map, a
search in Google maps should locate the place exactly, as it did the small
village where my own ancestors lived. The way the address is formulated
suggests that the birth took place while the village was under French rule,
which means that there is likely to be a birth certificate in the local
civil archives, giving the names of the parents. In 1808 Kreutznach, which
was part of the Kreis (Arrondissement) Koblenz, became part of the
Confederation of the Rhine, and it's to Koblenz I'd look for the
documentation. I must warn you that the original record may well not only be
in French, but may also use the French Revolutionary Calendar.
St Albans, UK.