I am not able to login to leopard after the 10.5.5 upgrade. the screen stall at the mac logo and the spinning wheel. I was not able to login in safemode. I logged in using the installation disk and did a disk and permission repair to no avail. I logged in using verbose mode and this is the message that i got (repeated all the time):

(computer name) com.apple.launchd[1] (com.apple.mDNSResponder(270/1/2/3/...): getpwnam('_mdnsresponder") failed

any help is much appreciated