I am seeing the exact same problem on Feisty Fawn, kernel version 2.6.20-14 too. (After the update of 11/4/2007 (but i'm not really sure of the date)).
With the same uuid I can boot with the old kernel (I upgrade from edgy) 2.6.17-10-generic (2.6.17-11-generic don't go).


My Grub
reef@portatireef:~$ cat /boot/grub/menu.lst
default         0

timeout         10

title           Ubuntu, kernel 2.6.20-14-lowlatency
root            (hd0,3)
kernel          /boot/vmlinuz-2.6.20-14-lowlatency root=UUID=dd2fff11-bfc0-4235-8557-ad9679166a1f ro quiet splash
initrd          /boot/initrd.img-2.6.20-14-lowlatency
quiet
savedefault

title           Ubuntu, kernel 2.6.20-14-lowlatency (recovery mode)
root            (hd0,3)
kernel          /boot/vmlinuz-2.6.20-14-lowlatency root=UUID=dd2fff11-bfc0-4235-8557-ad9679166a1f ro single
initrd          /boot/initrd.img-2.6.20-14-lowlatency

title           Ubuntu, kernel 2.6.20-14-generic
root            (hd0,3)
kernel          /boot/vmlinuz-2.6.20-14-generic root=UUID=dd2fff11-bfc0-4235-8557-ad9679166a1f ro quiet splash
initrd          /boot/initrd.img-2.6.20-14-generic
quiet
savedefault

title           Ubuntu, kernel 2.6.20-14-generic (recovery mode)
root            (hd0,3)
kernel          /boot/vmlinuz-2.6.20-14-generic root=UUID=dd2fff11-bfc0-4235-8557-ad9679166a1f ro single
initrd          /boot/initrd.img-2.6.20-14-generic

title           Ubuntu, kernel 2.6.17-10-generic
root            (hd0,3)
kernel          /boot/vmlinuz-2.6.17-10-generic root=UUID=dd2fff11-bfc0-4235-8557-ad9679166a1f ro quiet splash
initrd          /boot/initrd.img-2.6.17-10-generic
quiet
savedefault

title           Ubuntu, kernel 2.6.17-10-generic (recovery mode)
root            (hd0,3)
kernel          /boot/vmlinuz-2.6.17-10-generic root=UUID=dd2fff11-bfc0-4235-8557-ad9679166a1f ro single
initrd          /boot/initrd.img-2.6.17-10-generic

title           Ubuntu, memtest86+
root            (hd0,3)
kernel          /boot/memtest86+.bin
quiet

### END DEBIAN AUTOMAGIC KERNELS LIST

# This is a divider, added to separate the menu items below from the Debian
# ones.
title           Other operating systems:
root


# This entry automatically added by the Debian installer for a non-linux OS
# on /dev/hda1
title           Microsoft Windows XP Professional
root            (hd0,0)
savedefault
makeactive
chainloader     +1

My lspci
reef@portatireef:~$ lspci
00:00.0 Host bridge: Silicon Integrated Systems [SiS] 755 Host (rev 01)
00:01.0 PCI bridge: Silicon Integrated Systems [SiS] SG86C202
00:02.0 ISA bridge: Silicon Integrated Systems [SiS] SiS963 [MuTIOL Media IO] (rev 25)
00:02.1 SMBus: Silicon Integrated Systems [SiS] SiS961/2 SMBus Controller
00:02.5 IDE interface: Silicon Integrated Systems [SiS] 5513 [IDE]
00:02.6 Modem: Silicon Integrated Systems [SiS] AC'97 Modem Controller (rev a0)
00:02.7 Multimedia audio controller: Silicon Integrated Systems [SiS] AC'97 Sound Controller (rev a0)
00:03.0 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller (rev 0f)
00:03.1 USB Controller: Silicon Integrated Systems [SiS] USB 1.0 Controller (rev 0f)
00:03.3 USB Controller: Silicon Integrated Systems [SiS] USB 2.0 Controller
00:04.0 Ethernet controller: Silicon Integrated Systems [SiS] SiS900 PCI Fast Ethernet (rev 91)
00:06.0 FireWire (IEEE 1394): Texas Instruments TSB43AB22/A IEEE-1394a-2000 Controller (PHY/Link)
00:09.0 CardBus bridge: O2 Micro, Inc. OZ711M1/MC1 4-in-1 MemoryCardBus Controller (rev 20)
00:09.1 CardBus bridge: O2 Micro, Inc. OZ711M1/MC1 4-in-1 MemoryCardBus Controller (rev 20)
00:09.2 System peripheral: O2 Micro, Inc. OZ711Mx 4-in-1 MemoryCardBus Accelerator
00:0b.0 Network controller: Intel Corporation PRO/Wireless 2200BG Network Connection (rev 05)
00:18.0 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] HyperTransport Technology Configuration
00:18.1 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Address Map
00:18.2 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] DRAM Controller
00:18.3 Host bridge: Advanced Micro Devices [AMD] K8 [Athlon64/Opteron] Miscellaneous Control
01:00.0 VGA compatible controller: ATI Technologies Inc RV350 [Mobility Radeon 9600 M10]

bye