FC3 Kernel Panic - not syncing with old recompiled kernel

[Admin]

Hi
I've just upgraded from FC2 -> FC3 and I'm having trouble compiling a 
working kernel.
My old 2.6.8.1 kernel which was compiled under FC2 works just fine 
under FC3, but when I recompile it under FC3 I get the following 
errors:

Uncompressing Linux... Ok, booting the kernel
audit(1101046871.4294965592:0): inititalized
Red Hat nash version 4.1.18 starting
mkrootdev: label /1 not found
mount: error 2 mounting ext3
mount: error 2 mounting none
  switchroot:  mount failed:  22
  umount /initrd/dev failed: 2
  Kernel panic - not syncing: Attempted to kill init!

If I change grub.conf to my root device /dev/sdb5 instead of LABEL=/1 I 
get the same errors but without the 'label /1 not found' error and - 
mount: error 6 mounting ext3

I've tried the FC3 kernel source and 2.6.9 from kernel.org and always 
the same errors.
I see from the list that there are similar problems with the latest 
kernel rpm but I can't even recompile an old kernel source that was 
previously working.

# lspci
00:00.0 Host bridge: Intel Corp. 82845G/GL[Brookdale-G]/GE/PE DRAM 
Controller/Host-Hub Interface (rev 01)
00:02.0 VGA compatible controller: Intel Corp. 
82845G/GL[Brookdale-G]/GE Chipset Integrated Graphics Device (rev 01)
00:1d.0 USB Controller: Intel Corp. 82801DB/DBL/DBM 
(ICH4/ICH4-L/ICH4-M) USB UHCI Controller #1 (rev 01)
00:1d.1 USB Controller: Intel Corp. 82801DB/DBL/DBM 
(ICH4/ICH4-L/ICH4-M) USB UHCI Controller #2 (rev 01)
00:1d.2 USB Controller: Intel Corp. 82801DB/DBL/DBM 
(ICH4/ICH4-L/ICH4-M) USB UHCI Controller #3 (rev 01)
00:1d.7 USB Controller: Intel Corp. 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI 
Controller (rev 01)
00:1e.0 PCI bridge: Intel Corp. 82801 PCI Bridge (rev 81)
00:1f.0 ISA bridge: Intel Corp. 82801DB/DBL (ICH4/ICH4-L) LPC Interface 
Bridge (rev 01)
00:1f.1 IDE interface: Intel Corp. 82801DB (ICH4) IDE Controller (rev 
01)
00:1f.3 SMBus: Intel Corp. 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) SMBus 
Controller (rev 01)
00:1f.5 Multimedia audio controller: Intel Corp. 82801DB/DBL/DBM 
(ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 01)
01:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. 
RTL-8139/8139C/8139C+ (rev 10)
01:01.0 SCSI storage controller: Adaptec AIC-7892A U160/m (rev 02)
01:02.0 Ethernet controller: Realtek Semiconductor Co., Ltd. 
RTL-8139/8139C/8139C+ (rev 10)

Am I missing something really obvious?
I'd appreciate some pointers.

Thanks
Phill Ashworth