VBox: "Unsupported version 2 of data unit" after snapshot was restored

[Yuri]

After I restored the snapshot (of Windows 7 guest) I get such error 
while launching the machine again:
"Unsupported version 2 of data unit '8237A" (instance #0, pass 0xffffffff)
(VERR_SSM_UNSUPPORTED_DATA_UNIT_VERSION)

I am not sure if this is FreeBSD specific or generic.

FreeBSD-9.0-STABLE amd64
virtualbox-ose-4.0.14

Yuri