OK, try again. This time clean .tar.bz2. sh BUILD warning: skipping optional Message Passing Interface (MPI) library. note: to enable MPI support, add "using mpi ;" to user-config.jam. note: to suppress this message, pass "--without-mpi" to bjam. note: otherwise, you can safely ignore this message. Note: Building Boost.Regex with Unicode/ICU support enabled Using ICU in /usr/include /usr/local/src/boost_1_39_0_beta1/tools/build/v2/build/virtual- target.jam:1056: in virtual-target.register-actual-name from module virtual- target error: Duplicate name of actual target: <pstage/lib>libboost_date_time.so.1.39.0 error: previous virtual target { common%common.copy- libboost_date_time.so.1.39.0.SHARED_LIB { gcc%gcc.link.dll- libboost_date_time.so.1.39.0.SHARED_LIB { gcc%gcc.compile.c++- gregorian/greg_month.o.OBJ { gregorian/greg_month.cpp.CPP } } { gcc%gcc.compile.c++-gregorian/greg_weekday.o.OBJ { gregorian/greg_weekday.cpp.CPP } } { gcc%gcc.compile.c++- gregorian/date_generators.o.OBJ { gregorian/date_generators.cpp.CPP } } } } error: created from ./stage-proper error: another virtual target { common%common.copy- libboost_date_time.so.1.39.0.SHARED_LIB { gcc%gcc.link.dll- libboost_date_time.so.1.39.0.SHARED_LIB { gcc%gcc.compile.c++- gregorian/greg_month.o.OBJ { gregorian/greg_month.cpp.CPP } } { gcc%gcc.compile.c++-gregorian/greg_weekday.o.OBJ { gregorian/greg_weekday.cpp.CPP } } { gcc%gcc.compile.c++- gregorian/date_generators.o.OBJ { gregorian/date_generators.cpp.CPP } } } } error: created from ./stage-proper error: added properties: <threading>multi error: removed properties: <threading>single /usr/local/src/boost_1_39_0_beta1/tools/build/v2/build/virtual- target.jam:480: in actualize-no-scanner from module object(file-target)@4671 /usr/local/src/boost_1_39_0_beta1/tools/build/v2/build/virtual- target.jam:130: in object(file-target)@4671.actualize from module object(file-target)@4671 /usr/local/src/boost_1_39_0_beta1/tools/build/v2/build-system.jam:713: in load from module build-system /usr/local/src/boost_1_39_0_beta1/tools/build/v2/kernel/modules.jam:283: in import from module modules /usr/local/src/boost_1_39_0_beta1/tools/build/v2/kernel/bootstrap.jam:138: in boost-build from module /usr/local/src/boost_1_39_0_beta1/boost-build.jam:16: in module scope from module