Unfortunately Mahren means Moravia.
The Czech Republic's phone book is at http://phone.quick.cz
and the name KOPRIVA lists in Zlinsky kraj in the town of Zlin, Lesna and few others. That is the only place I looked.
The Ellis Island website is listing 92 Koprivas as passing thru that port to America.
There are several towns that start with the name Morav... like Moravec, Moravska .., Moravsko.
You will need to locate a name of a town in order to further your research.http://mapy.atlas.cz
for location of a townhttp://mesta.obce.cz
for information on some towns
Is Frantisek's (Frank) manifest on the Ellis Island as I do not see a Frantisek arriving in 1912.