I get this error when trying to start a dev instance after the latest update. I ran setup.py bootstrap and it appears lighttpd was not installed.
2011-01-28 10:49:44 [15040] [INFO] Starting gunicorn 0.12.0
2011-01-28 10:49:44,122 CRIT uncaptured python exception, closing channel <POutputDispatcher at 167071052 for <Subprocess at 166905004 with name openlibrary in state RUNNING> (stdout)> (<type 'exceptions.IOError'>:[Errno 29] Illegal seek [/home/mang/pyenvs/ol/lib/python2.6/site-packages/supervisor-3.0a9-py2.6.egg/supervisor/supervisord.py|runforever|245] [/home/mang/pyenvs/ol/lib/python2.6/site-packages/supervisor-3.0a9-py2.6.egg/supervisor/dispatchers.py|handle_read_event|242] [/home/mang/pyenvs/ol/lib/python2.6/site-packages/supervisor-3.0a9-py2.6.egg/supervisor/dispatchers.py|record_output|176] [/home/mang/pyenvs/ol/lib/python2.6/site-packages/supervisor-3.0a9-py2.6.egg/supervisor/dispatchers.py|_log|152] [/home/mang/pyenvs/ol/lib/python2.6/site-packages/supervisor-3.0a9-py2.6.egg/supervisor/loggers.py|info|281] [/home/mang/pyenvs/ol/lib/python2.6/site-packages/supervisor-3.0a9-py2.6.egg/supervisor/loggers.py|log|299] [/home/mang/pyenvs/ol/lib/python2.6/site-packages/supervisor-3.0a9-py2.6.egg/supervisor/loggers.py|emit|194] [/home/mang/pyenvs/ol/lib/python2.6/site-packages/supervisor-3.0a9-py2.6.egg/supervisor/loggers.py|doRollover|203])
2011-01-28 10:49:45,678 INFO spawnerr: can't find command 'lighttpd'
Installing lighttpd via apt-get allows the dev instance to start. lighttpd should be added to the dependencies.