A few of the resource bitmaps are named differently than their name listed in the resource file. This matters when building on a case sensitive file system.
The fix is simple - in the WinFormsUI/Docking/Resources directory just do:
svn mv Dockindicator_PaneDiamond_Fill.bmp DockIndicator_PaneDiamond_Fill.bmp
svn mv DockIndicator_PaneDiamond_Hotspot.bmp DockIndicator_PaneDiamond_HotSpot.bmp
svn mv DockIndicator_PaneDiamond_HotspotIndex.bmp DockIndicator_PaneDiamond_HotSpotIndex.bmp