I use Ubuntu 14.04 LTS and I compiled the source from github (Latest commit ed6e748 10 hours ago, if that helps) and when I start the Pipeline.exe and try to compile a .png it says libfreeimage-3.17.0.so is missing.
When I try an .fbx, the Assimp32.so is missing.
Where do I have to put those, I mean they are already in MonoGame/ThirdParty/Dependencies/.
Also I made sure the .png/.fbx are in the same folder as the .mgcb.
I saw a similar problem here:
Long story short, the libraries are compiled on a newer version of Ubuntu and they don’t work on any older versions of it, and no one cared enough to recompile them. Ubuntu 16.04 will work just fine.