TextureAnim problem

Hi! I'm using this code to animate a texture in a prim.

At the beginning it works fine but some seconds later it misconfigures the speed (goes much faster ) and the size of the animation texture image.

How can I avoid that, and how do i get this working fine?

If you need to know any more info let me know.

      default
      {
          state_entry()
          {
llSetTextureAnim(ANIM_ON | SMOOTH | LOOP, ALL_SIDES, 0, 1, 0.0, 0.0, 0.75);
          }
      
      }