[CentOS] Help recovering from an LVM issue

Hi People

I just updated a CentOS 5.2 Server that is a Guest inside VMware ESX 
3.50 Server using  "yum update".  As far as I can tell the only three 
packages were updated

Jul 24 16:37:49 Updated: php-common - 5.1.6-20.el5_2.1.i386
Jul 24 16:37:50 Updated: php-cli - 5.1.6-20.el5_2.1.i386
Jul 24 16:37:50 Updated: php - 5.1.6-20.el5_2.1.i386

But when I rebooted the Server one of my Volume Groups VolGroup01 would 
not mount.  By removing all references to VolGroup1 in /etc/fstab I was 
able to get a system that boots.  Unfortunately I am not that familiar 
with LVM but using the following commands it looks like all the 
information about my logical volumes on VolGroup01 is gone is this 
correct?  Is there likely to be any chance of recovering from this ?

vgscan
  Reading all physical volumes.  This may take a while...
  Found volume group "VolGroup01" using metadata type lvm2
  Found volume group "VolGroup00" using metadata type lvm2

pvs --units=h
  PV         VG         Fmt  Attr PSize  PFree
  /dev/sda2  VolGroup00 lvm2 a-    9.88G     0
  /dev/sda3  VolGroup00 lvm2 a-   90.00G     0
  /dev/sdb1  VolGroup01 lvm2 a-   19.97G 19.97G

 lvdisplay
  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol00
  VG Name                VolGroup00
  LV UUID                cEWsVM-8M8w-0gWY-FFoh-bGLT-sf0M-sbosUD
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                98.00 GB
  Current LE             3136
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol01
  VG Name                VolGroup00
  LV UUID                B8Y0UO-LATT-ohl2-kvfZ-bO1W-4cP8-3a6pVz
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                1.88 GB
  Current LE             60
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1

Thank you for any advice you may have relating to this.