I would ring up a tile adhesive company such as Ardex or Davco and ask theor technical support dudes. They are quite helpful. Just have all the information at hand regarding your floor. E.g. is the house on stumps? If so, what is the joist spacing? etc.
If the house is on stumps you will need a flexible tile adhesive. Once again, tech support at Ardex or Davco could help you out. Personally I dealt with Ardex on my last tiling project and they were very helpful to point me to the right products to use.