Typically "Land Lock" means the property is surrounded by other private property and there is no access without permission from neighboring property owners. Land lock property is usually very cheap because you may have trouble getting onto your property. If your property is Land locked you must have permission to cross other private property to get to yours - unless, of course, you own a helicpoter.
In the USA some states prohibit neighboring property owners from denying you access to what you rightfully own, some don't.
Best bet is to check local law and don't buy the property until you fully understands the existing conditions, or you own a helicopter!

I am a little confused in reading the last paragraph, "In the USA some states prohibit neighboring etc." Do these States include Virginia, or are they other States?