Actually, the simple fact is that there are no (known) mathematical, nor physical, constraints that eliminate the possibility using a "Space Warp" as a means of getting from point-A to point-B faster than the speed of light would, seem to, allow. This is actually fairly-well established.
The real-problems come from a few more, down-to-Earth, elements:
1. Gravity (and the associated warping of space) are only now beginning to actually be understood, at the underlying-mechanisms-level (though, I believe that "M-Theory" has begun to show some real promise in this area, possibly explaining the fundamental mechanisms, and behavior, of gravity).
2. Most, theoretical, ideas regarding this phenomena still require almost unbelievable energy-levels (energy-levels that are simply beyond any current ability to generate, measure, or utilize).
3. The hard-science that would be necessary to begin to actually delve into such possibilities ("Warp-Drive" propelled spaceships), has been, and is being, seriously hampered by continually bone-headed "policy", and funding, issues within governments (with regards to, long-term, "big-science" goals).
4. Actually engineering, and funding, this sort of endeavor... would seem to be a near impossibility at this point.
However, this would be the ultimate long-term science-endeavor. And, I have little doubt that the water-shed of knowledge (to Physics, Cosmology, and technology) that pursuing such a long-term goal would achieve, certainly has enormous potential-value, and merit.
Besides, "Warp-Driven Space-Ships" would be really, really, cool...
Oh... And, as to a few Physics-misnomers...
Einstein proved (mathematically) that Light-speed (C) was a constant in normal-space, and that, to accelerate any mass (M) to the speed of light, would effectively require infinite energy (E). This means that no mass can travel at the speed of light (or faster), in normal-space. And, "Relativity" means that no object can appear to be traveling faster than the speed of light, to any observer. If two objects are, in fact, traveling faster than the speed of light (relative to each other) the actual observed phenomena is a frequency (or, Energy-Level) shift... not, an observation of faster-than-light travel. But, none of this dissuades the possibilities of "warping space" (which Einstein, also absolutely-proved to be a, very-real, phenomena).