All the cases have the mesh already converted for OpenFOAM and the constant/polyMesh folder as required to run the case. 
Hence, there is no need to run gmshToFoam command.

If gmshToFoam command is used, the constant/polyMesh/boundary file generated will need to be modified as such:
'frontAndBack' patch entries for the fields 'type' and 'physicalType' must be changed from 'patch' to 'empty' in order to run the 2D case. 