According to the publicly available period records of the Serbian Trade Association, one Kristian Molter owned a tailoring business in Vrbas in years 1907 and 1913 - so before and after your ancestor emigrated, confirming that the family lived in that town.
More Molters are listed later in the village of Plandište ( old name Mariolana), as well as Molter Jovan in Vrbas again in 1940.
Records for Roman Catholic Church are available online for Vrbas via Kalocsa Diocese e-archive, but from what I can see the years available do not cover the birth year of your ancestor. This may be due to the fact that older records are under an earlier established parish - I will let you know about that once I check the books on parish histories in that area.
More on Kalocsa diocese e-archive (Vrbas is listed under its name in Hungarian language -Újverbász).
I will try to locate a record of anything relating to your ancestor in Vrbas parish - marriage or birth records of children, and only when you have such a confirmed starting point I would advise you register for this e-archive, because there is a registration fee for using it.
"Rodoslovlje" Serbian Genealogy Society www.rodoslovlje.com