Why does Help not build?

When building the current CVS head with Microsoft Visual Studio 2008 Professional C++:
File not found - manual.audacityteam.org


30>------ Build started: Project: help, Configuration: Debug Win32 ------
30>Performing Pre-Build Event…
30>‘python’ is not recognized as an internal or external command,
30>operable program or batch file.
30>The system cannot find the file specified.
30>File not found - manual.audacityteam.org
30>0 File(s) copied
30>The system cannot find the file specified.
30>Project : error PRJ0002 : Error result 2 returned from ‘C:WindowsSysWow64cmd.exe’.
30>Build log was saved at “file://d:audioAudacitycurrentCVSaudacitywinProjectshelpDebugBuildLog.htm”
30>help - 1 error(s), 0 warning(s)


4>------ Build started: Project: help, Configuration: Debug Win32 ------
4>Performing Pre-Build Event…
4>0 File(s) copied
4>Build log was saved at “file://d:audioAudacitycurrentCVSaudacitywinProjectshelpDebugBuildLog.htm”
4>help - 0 error(s), 0 warning(s)