Has little to do with Code::Blocks.
Try wxWidgets docs.
http://svn.wxwidgets.org/svn/wx/wxWidgets/trunk/docs/tech/tn0003.txt
http://svn.wxwidgets.org/svn/wx/wxWidgets/trunk/docs/doxygen/regen.bat
My batch file (make_wx29x_doxy_chm.bat)
REM http://svn.wxwidgets.org/svn/wx/wxWidgets/trunk/docs/tech/tn0003.txt
REM http://www.stack.nl/~dimitri/doxygen/commands.html
SET PATH=C:\Program Files (x86)\doxygen\bin;C:\Program Files (x86)\Graphviz 2.21\bin;%PATH%
SET HHC_PATH=C:\Program Files (x86)\HTML Help Workshop
CD wxWidgets-2.9.x
setlocal
set WX=%CD%
cd %WX%\docs\doxygen
CALL regen.bat
TYPE doxygen.log
PAUSE