, ok, understood...unfortunately I just discovered OMV-3.0 iso is available only for AMD64, so I can't install using my laptop based on i7 x86 processor. Question about x86 iso availability posted on proper thread.
Check your bios. All i7 process should be able to do 64 bit.
As for virtualbox problem, that is because the virtualbox package mirror is still down as mentioned in one of my above posts.