virtualbox.org

Virtualbox was working great, but today, with no apparent changes to the host, all virtual machines give the same error when trying to boot:
"A critical error occurred during execution of the virtual machine and has been stopped"
The Host is Windows 7 64 and the virtual machines too.
Attached the log of one of them.
Could you help me? Thank you

00:00:17.737041 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
00:00:17.737042 !!
00:00:17.737042 !! VCPU0: Guru Meditation -2708 (VERR_VMM_SET_JMP_ABORTED_RESUME)
00:00:17.737229 !!
00:00:17.737235 !! ACTIVE TRAP=0e ERRCD=2 CR2=00000001d6b80000 PC=fffff8000c1136d0 Type=0 cbInstr=ff fIcebp=false (Guest!)

Discussed many times. E.g. see viewtopic.php?f=6&t=105656.