[linux-audio-user] Jack/Hydrogen problem

I start Jack with qjackctl and everything's fine with Ardour. But when I try to start Hydrogen, it says "Error starting audio driver". I have tried to change jack as audio driver and restart it, but the same error message appears. With alsa driver it works fine. system information: Mandriva LE 2005 2.6.11-9.mm.9mdk From the console (it says Jack is not running, though it is - and I am not running jack as root): $ ./hydrogen Warning: no locale found: /home/linna/hydrogen-0.9.2-x86/bin/data/i18n/hydrogen.fi_FI Hydrogen 0.9.2-x86 [Jul 20 2005] [http://www.hydrogen-music.org] Copyright 2002-2005 Alessandro Cominu Compiled modules: (FLAC) (Jack) (Alsa) (OSS) (LRDF) Hydrogen comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions. See the file COPYING for details Using data path: /home/linna/hydrogen-0.9.2-x86/bin/data [WARNING] SongReader [readXmlString] Using default value in drumkit [LadspaFX::load] INIT - /usr/lib/ladspa//tap_reverb.so - tap_reverb [WARNING] LadspaFX [LadspaFX::load] integer hint not implemented yet [LadspaFX::getPluginList] reading directory: /usr/lib/ladspa/ [LadspaFX::getLadspaFXGroup] [LadspaFX::getPluginList] reading directory: /usr/lib/ladspa/ [WARNING] JackDriver Jack server not running? [ERROR] Hydrogen [audioEngine_startAudioDrivers] Error starting audio driver [audioDriver::init()] [ERROR] Hydrogen [audioEngine_startAudioDrivers] Error starting audio driver [ERROR] Hydrogen [audioEngine_startAudioDrivers] Using the NULL output audio driver [ERROR] Hydrogen [audioEngine_startAudioDrivers] m_pMainBuffer_L== NULL [ERROR] Hydrogen [audioEngine_startAudioDrivers] m_pMainBuffer_R== NULL [ERROR] Hydrogen [audioEngine_setupLadspaFX] nBufferSize=0 [ERROR] NullDriver [setBpm] not implemented yet [ERROR] LocalFileMng [loadDrumkit] Load Instrument: Data file /home/linna/hydrogen-0.9.2-x86/bin/data/drumkits/CVS/drumkit.xml not found. [ERROR] MainForm [errorEvent] [WARNING] JackDriver Jack server not running? [ERROR] Hydrogen [audioEngine_startAudioDrivers] Error starting audio driver [audioDriver::init()] [ERROR] Hydrogen [audioEngine_startAudioDrivers] Error starting audio driver [ERROR] Hydrogen [audioEngine_startAudioDrivers] Using the NULL output audio driver [ERROR] NullDriver [setBpm] not implemented yet [ERROR] Hydrogen [audioEngine_startAudioDrivers] m_pMainBuffer_L== NULL [ERROR] Hydrogen [audioEngine_startAudioDrivers] m_pMainBuffer_R== NULL [ERROR] Hydrogen [audioEngine_setupLadspaFX] nBufferSize=0 [ERROR] MainForm [errorEvent]