vmsnap and vmrestore that was used to backup and restore vmwesx 2.5 (esx2.x) VMs & vmdk’s have been replaced in vmwesx 3 with VMWVCB vcbMounter and vcbRestore
you will also need to get version 3 of vmbk.pl if you are using that to backup your VMs
# vcbUtil -u root -p password -c ping
# vcbUtil -u root -p password -c resourcepools
# vcbUtil -u root -p password -c vmfolders
# vcbVmName -u root -p password -s any:
# vcbMounter -u root -p password -a powerstate:off -r /vmimages/off
# vcbMounter -u root -p password -a moref:96 -r /vmimages/centos3
# vcbMounter -u root -p password -a name:centos4 -r /vmimages/centos4
# vcbMounter -u root -p password -a uuid:65D4EE45 -r /vmimages/centos5
# vcbMounter -u root -p password -a moref:16 -r /vmimages/rhel4
# vcbRestore -u root -p password -s /vmimages/off/ -b overwrite
See
http://www.vmware.com/products/beta/esx-vc/vcb-cos-esx30-usage.html
http://www.petri.co.il/vmware-consolidated-backup-utilities.htm