Hello Jacek,
the log you are showing us is the VirtualBox log, not the ReactOS log.
To get the ReactOS log in VirtualBox please read following page at ReactOS wiki:
  From: stacheldraht(a)interia.pl
 To: ros-general(a)reactos.org
 Date: Sat, 21 Feb 2009 20:08:12 +0100
 Subject: [ros-general] ReactOS on VirtualBox 2.0.6
 Hello everybody,
 I am now trying to test the last release of ReactOS on VirtualBox 2.0.6 with
 Windows XP as preset guest system. However, I encounter reproducible crashes
 at boot time. This is what the log says:
 00:36:00.871
 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 00:36:01.871 Changing the VM state from 'RUNNING' to 'GURU_MEDITATION'.
 00:36:01.921 Display::handleDisplayResize(): uScreenId = 0,
 pvVRAM=00007fe1d2a52000 w=640 h=480 bpp=0 cbLine=0x140
 00:36:01.921 ERROR [COM]: aRC=NS_ERROR_FAILURE (0x80004005)
 aIID={09789f63-4525-48e5-a5e4-1080453b0eab} aComponent={Display} aText={Could
 not take a screenshot (VERR_BUFFER_OVERFLOW)} aWarning=false, preserve=false
 00:36:06.416 Console::powerDown(): A request to power off the VM has been
 issued (mMachineState=6, InUninit=0)
 00:36:06.417 vboxClipboardDestroy: shutting down host clipboard
 00:36:06.421 Shared clipboard: host clipboard thread terminated successfully
 00:36:06.425 Changing the VM state from 'GURU_MEDITATION' to 'OFF'.
 00:36:06.425 Changing the VM state from 'OFF' to 'DESTROYING'.
 Any idea of the reason? All useful hints are appreciated.
 Regards
 Jacek Rużyczka
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