Hmm, unfortunately you chose an incomplete mesh file format
My3d does not support texture coord transformations, but your scene does. Even though the giles exporter is aware of such transformations, or at least could use them easily, it simply ignores them. So yo have to change the texture mapping inside giles to avoid texture scaling, but use absolute coords instead.
You can also contact the MY3D author and request a new version supporting texture matrices, or at least to fix the exporter and calculate absolute texture coords from the given coords and the transformations. I won't change the format (as it is a proprietary format anyway, even though it's public domain) and also not the exporter (as it is a Giles' or whatever tool's problem). Sorry.
