Some problems, needed to change:
toggleBtns[n] = toggleControls[n].toggleBtn;
to
toggleBtns[n] = toggleControls[n];
I don't really even know if that makes sense.
line 66 in tk2dUIToggleControlGroup.cs
And lots of errors when trying to build with monodevelop, which are alike this one:
TK2DROOT\tk2d\Editor\Tilemap\tk2dTileMapUtility.cs(7,7): Error CS0246: The type or namespace name 'tk2dRuntime' could not be found (are you missing a using directive or an assembly reference?) (CS0246) (Assembly-CSharp-Editor)