Make spins with THREADS>1 on Win 7

Hi all, Trying to get a build going on Win 7. On both the 32-bit and the 64-bit version running 'sh validate' stalls at "inplace/bin/mkdirhier" utils/touchy/dist/build/tmp//. At this point nothing happens, other than that I seem to have 100% CPU usage; 'ps' only shows two make processes, but no further subprocesses. Not sure what's going on here. Running 'sh validate --no-clean' after killing both make processes at this point stalls at the same point; running it with THREADS=1 seems to resolve the issue. Anybody any idea what might be going on? Edsko