To quote davido

Please make sure when you cross-post that you identify such, so that people here (or there) don't end up working on a problem that is solved. Identifying cross-posting will promote collaborative progress too. Getting a bunch of people doing research for you in parallel without knowing about each others' progress defeats the collaboration aspect of public forums.

Already answered at http://stackoverflow.com/questions/7834536/run-perl-script-while-computer-is-locked/7834995