Can't install RAIDar in OS X

Hi, all! Just purchased a ReadyNAS Duo v2 and equipped it with a Western Digital WD20EARX approved drive. I am running OS X 10.5.8 on an Intel 2.4 GHz Core 2 Duo iMac with 4 GB of memory. The NAS is attached to an Airport Extreme 802.11n base station, and appears under the "shared disks" header in the list of drives. But I can't get RAIDar installer to work. I first used the disk image on the CD-ROM packed with the NAS. Then I downloaded RAIDar for Mac OS X from the support site (www.ReadyNAS.com/start). Both the disk and the download are RAIDar installer 4.3.4. In each case, I mount the disk image, highlight the "RAIDar installer" icon, then select "open." A dialog box appears asking you to confirm that you want to run the software, and the RAIDar installer icon appears in the dock with a pulsing blue dot as if it is booting. When you click the "open" button in the dialog box, however, the application quits and the RAIDar installed disappears from the dock. I've called Netgear support and they've promised to investigate, but I was wondering if anyone here had a suggestion to overcome this obstacle, which has me stuck at the initial step to install and use the Duo. Thanks for any ideas.