Nikon d7000 live-view AF problem?

When using the viewfinder, the AF works fine, but when using live view the AF can't get a lock at all, it tries to focus but can't. I have tried with two different lenses (both NIKKOR) and there's no difference, is this a known fault that can be fixed with a software update or do i need to send it in for repair?

In LiveView your camera can't use it's normal phase detection AF (Auto Focus) and instead has to rely on a less efficient contrast detection algorithm that uses the cameras main sensor. It's not a fault, but a common limitation of the focusing mechanism that affects all DSLR-type cameras other than Sony's SLT's which through the use of a semi-transparent mirror can still use the phase detection sensor full time.