I'm afraid that this code in the "Getting Started Working with rasters" section is wrong.
# creating the new FMERaster
rasterProperties = fmeobjects.FMERasterProperties(numRows, numCols,
xCellOrigin, yCellOrigin,
xSpacing, ySpacing,
xOrigin, yOrigin,
xRotation, yRotation)
According to the API reference, the order of parameters should be:
# creating the new FMERaster
rasterProperties = fmeobjects.FMERasterProperties(numRows, numCols,
xSpacing, ySpacing,
xCellOrigin, yCellOrigin,
xOrigin, yOrigin,
xRotation, yRotation)