Fresh install of 10.5 hangs at boot after 10.5.8 update

I'm troubleshooting a MacBook that hangs at start-up after installation of the 10.5.8 complete update. I've run Disk Utility (no errors), fsck (fixed a single error), and repair permissions (oddly, repaired a few on this fresh install). I've booted into verbose mode, and it appears that there's an infinite loop of:

localhost DirectoryService[#]: Launced version 5.8.1 (v514.28)

localhost ReportCrash[#]: Saved crashreport to /Library/Logs/CrashReporter/DirectoryService. . . .(it goes on, but it's just date info).

Again, this is a fresh installation of 10.5. The only programs that have been updated are those updated through Apple Update. I did have problems installing the 10.5.8 update through the Update utility because "the package contents could not be verified," but the update installed fine after I downloaded it from Apple's site.

Any ideas?