Someone

     [nant] /home/mike/source/opensim/OpenSim/Region/Environment/OpenSim.Region.Environment.dll.build build
            Buildfile: file:///home/mike/source/opensim/OpenSim/Region/Environment/OpenSim.Region.Environment.dll.build
            Target framework: Mono 2.0 Profile
            Target(s) specified: build 
            
            
            build:
            
                 [echo] Build Directory is /home/mike/source/opensim/OpenSim/Region/Environment/bin/Debug
                [mkdir] Creating directory '/home/mike/source/opensim/OpenSim/Region/Environment/bin/Debug'.
                  [csc] Compiling 115 files to '/home/mike/source/opensim/OpenSim/Region/Environment/bin/Debug/OpenSim.Region.Environment.dll'.
                  [csc] /home/mike/source/opensim/OpenSim/Region/Environment/Modules/Terrain/TerrainModule.cs(40,112): error CS0234: The type or namespace name `ITerrainModule' does not exist in the namespace `OpenSim.Region.Environment.Modules.Terrain'. Are you missing an assembly reference?
                  [csc] Compilation failed: 1 error(s), 0 warnings
            
            BUILD FAILED - 0 non-fatal error(s), 1 warning(s)
            
            /home/mike/source/opensim/OpenSim/Region/Environment/OpenSim.Region.Environment.dll.build(14,10):
            External Program Failed: /usr/lib/pkgconfig/../../lib/mono/2.0/gmcs.exe (return code was 1)
            
            Total time: 0.8 seconds.
            

BUILD FAILED

Nested build failed.  Refer to build log for exact reason.

Total time: 20.8 seconds.