Heterogeneous nodes in OpenMPI

Question

I am new to OpenMPI. I heard that it supports heterogeneous nodes. I have couple of raspberry-pis and an i7 machine with me. I have installed OpenMPI in all of them. I have also configured password-less ssh so that master (i7 pc) could launch a process in raspberry-pis.

When I run simple hello_MPI.exe using following command from i7 machine,

mpiexec -machinefile machinefile -n 2 hello_MPI.exe

Nothing happens! It hangs. However, hello_MPI.exe executes properly when I am working with only 2 r-pis (one of the r-pis is master in this case. i7 machine is not used as one of the computing nodes)

Additional information: hello_MPI.exe is in the same directory in all the nodes (2 raspberry-pi s and i7 machine). machinefile contains ip addresses of 2 raspberry-pis. .exe file on i7 machine and r-pi is not the same. i.e. the one on r-pi is compiled on r-pi and the one on i7 machine is compiled on i7 pc.

It will be very helpful for me if anyone could tell me what's happening here. Thanks!