im not sure if this is the problem, because i am far from an expert with shaders, but under the normal map sampler there should be a line like :
addressu = "something";
addressv = "something";


this is to define if that skin is clamped, wrapped or mirrored around an object, you want those variables to be "wrap" if its not there at all you may want to add them the total code would be:

AddressU=WRAP;
AddressV=WRAP;