VertexDisplacementMap V4 Colorize Error

When checking Colorize, the Op throws a shader error:

ERROR: 0:613: 'mod8_map' : no matching overloaded function found

#ifdef mod8_HEIGHTMAP_COLORIZE
613:    col.rgb*=mod8_map( mod8_displHeightMapColor, 0.0,1.0 , mod8_colorizeMin,mod8_colorizeMax);
614: #endif