Platformer2D - MSBuildExtensionsPath not set?!

[oliverlorenz]

Hey guys,

I got following error when I try to start the Platformer2D example in MonoDevelop while building:

Error: /path/to/example/MonoGame.Samples/Platformer2D/Platforms/Linux/Platformer2D.csproj: /path/to/example/MonoGame.Samples/Platformer2D/Platforms/Linux/Platformer2D.csproj could not import "$(MSBuildExtensionsPath)\MonoGame\v3.0\MonoGame.Content.Builder.targets" (Platformer2D)

I'm not a .NET professional, but in my research the MSBuildExtensionsPath is not set.

echo $(MSBuildExtensionsPath)
MSBuildExtensionsPath: Befehl nicht gefunden.

I use Ubuntu 14.04 and MonoDevelop 5.9.6 and installed monogame with the following guide: http://www.monogame.net/documentation/?page=Setting_Up_MonoGame_Linux

I hope somebody can halp me to solve this problem
Oli