The install is not working for me either. Only I did not use Rom Manager. I downloaded the zip file onto my phone then rebooted into ClockworkMod Recovery and selected the zip file. It looked like it was installing off the SD card but it happened so fast I had my suspicions. Sure enough, when the phone rebooted, no change. I deleted the zip file and re-downloaded it but still the same result.
For those having this problem... Flash sprecovery in ROM Manager and the reflash Clockworkmod recovery. Then reinstall from ROM Manager. Worked for me this time and I've had this before with other rom manager installs.