OpenNI – error CS0006: cannot find metadata file `System.Windows.Forms.dll’

During installing the OpenNi kinect drivers, found here: https://github.com/OpenNI/OpenNI, I came across this error:

make[1]: Entering directory `/home/alex/kinect/OpenNI/Platform/Linux-x86/Build/Samples/SimpleViewer.net’ gmcs -out:../../../Bin/Release/SimpleViewer.net.exe -target:winexe -unsafe -o+ -r:OpenNI.net.dll -r:System.Windows.Forms.dll -r:System.Drawing.dll -lib:../../../Bin/Release ../../../../../Samples/SimpleViewer.net/*.cs ../../Res/AssemblyInfo-OpenNI.cs error CS0006: cannot find metadata file `System.Windows.Forms.dll’ Compilation failed: 1 error(s), 0 warnings make[1]: *** [../../../Bin/Release/SimpleViewer.net.exe] Error 1 make[1]: Leaving directory `/home/alex/kinect/OpenNI/Platform/Linux-x86/Build/Samples/SimpleViewer.net’ make: *** [Samples/SimpleViewer.net] […]