Just downloaded Visual Studio Professional for Mac and I cannot seem to build anything as I always get the same error:
/Library/Frameworks/Mono.framework/Version
I hope not to come too late, I did the following to solve the problem:
Right click in the solution and select "Options",
Select tab Build -> Configurations,
In "Configuration A." select "Debug" and disable all builds marks and click accept,
Clean, rebuild and execute project.
I hope this helps.