You have to line the floor with hardboard before putting adhesive vinyl tiles down, they won't stay stuck to bare floorboards for long. You may find they 'slip' even when laid properly on hardboard. I personally wouldn't recommend them.
I did this a couple of years ago in my bathroom. I had to fix hardboard to the floor boards first, and then laid the floor tiles on top. As already mentioned by daffy, the tiles do not stay down for very long. I tried many different products to stick them down, but at most they only remained stuck for a couple of months. In the end I ripped it all up and laid some laminate flooring.
We have just removed these for the same reason. The edges and corners rolled up quite quickly but the centres stayed stuck down and were the devil to remove.