Hi,

As previously mentioned in other posts, one has to build bjam that comes with boost 1.45.0 in order to be able to build boost.
Just in case anybody tries to build it with mingw I had to change two lines in bootstrap.bat

I have added the mingw paramenter in line 13:
call .\build.bat mingw > ..\..\..\bjam.log

And changed toolset to gcc in line 33:
set toolset=gcc

Best regards,
Mau.

If you prefer, here it is the full bootstrap.bat changed script:

@ECHO OFF

REM Copyright (C) 2009 Vladimir Prus
REM
REM Distributed under the Boost Software License, Version 1.0.
REM (See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)

ECHO Building Boost.Jam build engine
if exist ".\tools\build\v2\engine\src\bin.ntx86\bjam.exe" del tools\build\v2\engine\src\bin.ntx86\bjam.exe
if exist ".\tools\build\v2\engine\src\bin.ntx86_64\bjam.exe" del tools\build\v2\engine\src\bin.ntx86_64\bjam.exe
cd tools\build\v2\engine\src

call .\build.bat mingw > ..\..\..\bjam.log
@ECHO OFF
cd ..\..\..\..\..

if exist ".\tools\build\v2\engine\src\bin.ntx86\bjam.exe" (
   copy .\tools\build\v2\engine\src\bin.ntx86\bjam.exe . > nul
   goto :bjam_built)

if exist ".\tools\build\v2\engine\src\bin.ntx86_64\bjam.exe" (
   copy .\tools\build\v2\engine\src\bin.ntx86_64\bjam.exe . > nul
   goto :bjam_built)

goto :bjam_failure

:bjam_built

REM Ideally, we should obtain the toolset that build.bat has
REM guessed. However, it uses setlocal at the start and does
REM export BOOST_JAM_TOOLSET, and I don't know how to do that
REM properly. Default to msvc for now.
set toolset=gcc

ECHO using %toolset% ; > project-config.jam

ECHO.
ECHO Bootstrapping is done. To build, run:
ECHO.
ECHO     .\bjam
ECHO.   
ECHO To adjust configuration, edit 'project-config.jam'.
ECHO Further information:
ECHO.
ECHO     - Command line help:
ECHO     .\bjam --help
ECHO.    
ECHO     - Getting started guide:
ECHO     http://boost.org/more/getting_started/windows.html
ECHO.    
ECHO     - Boost.Build documentation:
ECHO     http://www.boost.org/boost-build2/doc/html/index.html

goto :end

:bjam_failure

ECHO.
ECHO Failed to build Boost.Jam build engine.
ECHO Please consult bjam.log for furter diagnostics.
ECHO.
ECHO You can try to obtain a prebuilt binary from
ECHO.
ECHO    http://sf.net/project/showfiles.php?group_id=7586^&package_id=72941
ECHO.
ECHO Also, you can file an issue at http://svn.boost.org
ECHO Please attach bjam.log in that case.

goto :end

:end