Page does not print as it appears in the PDF or Xara

I've built a cover page; a Sun and rays leading out to the bleed. The problem I have is with the rays. I made a rectangle, closed it at one end so that it would be conical ( a skinny one, and blended a fill from yellow to white. The Sun is not as bright a yellow as it appears on the page, and there is no smooth blend in the rays. It turns out that basically they show as three colors, a kinda' green, kinda' pink and white, in solid blocks. is there something I did, or didn't do to accomplish my goal? The colors are RGB light yellow to white. Thanks.

I made a couple of changes to the XD5 file, took it back to Fed Ex and it printed beautifully. Question: Prior to I had everything on the cover page grouped. Could that have been the problem?