Could well be the conversion from sRGB to Adobe RGB. Bring the image into Photoshop (or similar) and convert it to Adobe RGB. I would also consider installing the Roland profile by locating it in the Versaworls installion folder, right clicking it and choosing install. In Photoshop (unsure about other programs) you will then be able to soft proof the image using that ICC profile. This will give you a good preview of how the image will print. Be cautious though, this method works best with a calibrated monitor. If you don't have a calibrated monitor I would suggest purchasing a Colormunki or Huey Pro.
EDIT: Alternatively, in the Quality tab in Versaworks under color calibration option choose properties and select sRGB in the color simulation target dropdown. This may help.