This may be a tad off-topic, but I couldn't find any reference to this relative to XEmacs, and the problem seems to be peculiar to bjam. If I try to run bjam under XEmacs, e.g. via M-x compile, M-x shell-command, or even from inside an XEmacs shell buffer (running CMD), I get the error "spawn: Invalid argument". More specifically, if I run it via shell-command, I get this: ===================== ...found 331 targets... ...updating 1 target... gcc-Archive-action ..\phys_sim\bin\libphys_sim.lib\gcc-nocygwin\debug\architecture-native\debug-symbols-on\inlining-off\optimization-off\profiling-off\rtti-on\runtime-build-debug\runtime-link-dynamic\threading-single\vtable-thunks-default\libphys_sim.lib spawn: Invalid argument ====================== ... which indicates that bjam is in fact starting, but has some problem. Or maybe the tools do. If I run it in the same directory from a regular command window, it works fine. I'm running XEmacs 21.4, with recently updated packages. The bjam executable was downloaded yesterday. (I'm trying to use it for something other than Boost, BTW.) The toolset I'm using is MinGW, the latest stable full-package release, with no package updates. Anyone have an idea what might be wrong? I'm getting tired of looking at my build output in a command window and then hunting for line numbers in my source code. :-)