Terraformer bugfix causes crash

After applying this bugfix (from the known issues thread) I get a crash while the main menu loads.
I have renamed this thread and added too it as the original error was my fault.

The fixed code:
Terrain terraformer flips imported heightmaps
First noted in: <= TGE 1.4.2
FIX:
In terraformer.cpp, replace bool Terraformer::loadGreyscale(U32, GBitmap*) with

bool Terraformer::loadGreyscale(U32 r, GBitmap *bmp)   
{   
   Heightfield *dst = getRegister(r);   
  
   for( U32 yh = 0, yb = blockSize - 1; yh < blockSize; yh ++, yb -- )   
      for( U32 x = 0; x < blockSize; x ++ )   
      {   
         ColorI color;   
         bmp->getColor(x,yb,color);   
         // compute the luminance of each RGB   
         dst->val(x, yh) = ((F32)color[0]) * (0.299f/256.0f) +   
                            ((F32)color[1]) * (0.587f/256.0f) +   
                            ((F32)color[2]) * (0.114f/256.0f);   
      }   
  
   return true;   
}

This returns no errors. It just crashes when the main menu inits.
Any ideas what may have caused this and how I may fix it? I'm clueless.

What I am trying to fix is This problem where the heightmap doesn't line up. I was hoping this fix would fix it.