On press OK button in Settings window, even if nothing has changed, i always get error box:
VirtualBox error: rc=0x80004001 Page fusion is only supported on 64-bit hosts (0x80004001)

Ubuntu 14.04.3 LTS
Linux vboxhost 3.13.0-62-generic #102-Ubuntu SMP Tue Aug 11 14:28:35 UTC 2015 i686 i686 i686 GNU/Linux