QTR-Quadtone RIP

Just got the latest IMac and have CS4. I have the R2400 printer. That works fine. I downloaded QuadtoneRIP and installed. Got a message saying the software package was installed correctly.I got all the way through the process for printing with Q but it does not print. I checked the print queue and it is there marked "error" and "there is an error with software installation. please reinstall software of contact the vendor".    Can anyone help with this? My understanding is that I do not have to have Ghostscript installed? 

Thanks,