This is a simple problem:
The texture isn't at 32x32 dimension (32x32, 64x64, 128x128, 256x256, 512x512)
The texture probably not in that size, of course any combination of the listed dimensions would work fine
The only way to fix that is, change the dimension of the texture to the appropiate one (for smaller file size: 12bx128, for keeping the Quality of the texture 512x512, but be warn, if your image was below those dimension, and you change the dimension to that size, then it will blurred)
For avoiding the 'credit clash' i strongly recommend you to ask permission of the original creator, or even ask him to change the size, and update the model