Running SimpleFOAM

Hello. I am trying to simulate a simple pipe with 2 inlets and 1 outlet. However, when I try to generate the files using SimpleFOAM, I get the following error message:

"Wrong number of arguments, expected 1 found 3"

What can this be due to? I have attached my 'hdf' file with the mesh created. I have created 1 'Inlet' group (with 2 faces), 1 'Outlet' group and 1 'Walls' group.

Thank you in advance!