datatype/md5sum error

[alice-st]

Hi!
I've been trying to run https://github.com/ethz-asl/waypoint_navigator and I constantly get this error:

I was told that i am using the wrong version of mav_comm, but no matter what version of mav_comm I use,i get the same error.
Is there a possible solution to this?

I use ubuntu 16.04 and ROS kinetic.
Thank you.