Looks like your c2 is wrong. c2 and c3 are taylor series values for calculating sin/cos in the shader. Also, you should probably include more significant digits for .5 pi, pi, and 2 pi, to give a more accurate representation. Same thing with the factorals in the taylor series. Also, and im not 100% sure about this, but in your action, you should probably change the 2nd skin to a normal map (using bmap_to_normals). I have a slightly different ATI demo for water shading that also incorporates an environment map as well (to give sky reflections in the water) that I was trying to convert (with little luck), but now that this one works, maybe Ill see if i can get the reflection stuff added in (no promises). Id also like to see the c11 - c15 constants get replaced by using the mtl matrix and mtl skills so that they can be tweaked at run time (maybe via a panel, hmm.. i see a water studio coming for this effect) so you can get just the right water look.

Edit: Here is the link for the OceanWater shader i was talking about.