If you're on Cygwin and run into the 'sem_init: Resource temporarily unavailable' problem: Current Cygwin python versions have problems with running out of PIDs, it is a known problem and there has been several discussions and bugreports related to it. As of today, the best solution seems to be to rebase the Cygwin libraries: 0> Make sure you have the rebaseall program, it can be downloaded using Cygwin's setup.exe 1> Shut down all Cygwin processes and services (including shells) 2> Start a regular Win command prompt ('cmd') 3> Start 'ash' 4> Start '/bin/rebaseall', expect this step to take some time.. 5> All done! This worked for me. -- Fredrik , 2007