'Path interpolate': Use this if you wish to 'blend' the colors of the generated star and the original 'current' path style. By setting this to say 80 or so, and using the random fill or fill factor, the colors are subtle variants of the original pre-plugin fill color.
'Spread': Not all the paths use the spread or curve feature but by setting the spread, more rounded shapes can be generated. The first column is the direction point modification in the horizontal, the second column for the vertical. In most cases, the vertical is more useful for flower designs. The first column is more useful for sharper path designs.
Manual for the Star Burst plug-in for Illustrator CS5 CS4 CS3 CS2 etc