OK. Thank you all for the suggestions and the homework. I'm going to spell out exactly what I did, for the sake of the poor souls who follow.

I verified the md5sum of the install iso file. It matches the one on the download page here.

• Applications -> Utilities -> Terminal.app in OSX.
• Command: md5 and then the path to the iso file.

I found the SATA Controller model by doing the following (which I found here thanks to Dave.Mishchenko)

• During the load, when ESXi 4 fails, it prints: Failed to find boot partition
• Pressed ALT - F1: Nothing visible happens
• Typed "unsupported": No text appeared
• Pressed Enter
• Got a warning and a password prompt
• Pressed Enter
• Command prompt appeared
• Typed "Lspci -v | grep storage"
• Pressed Enter
• Saw the following:
  • "00:07.00 IDE interface Mass storage controller: nVidia Corporation CK804 Serial ATA Controller
  • "00:08.00 IDE interface Mass storage controller: nVidia Corporation CK804 Serial ATA Controller

I read the rest of that second thread (this one) and was a little discouraged. My only SATA Controller options from the BIOS are "ATA Mode" and "Off". "Off", well, shuts the thing off, and thereafter my hard drive isn't recognized. So ATA Mode is my only option. The only other suggestions are to install to a flash drive or to get a new SATA controller.

Other suggestions please?

Installing to a flash drive is ESXi 4.0 Embedded, correct? The compatibility list shows:

Partner Name\	Model\	CPU Series\	Supported Releases
DELL	PowerEdge T105\	AMD Opteron 13xx Series\	ESX 4.0\1\ , ESXi 4.0 Installable\1\

If the supported version doesn't work, why would the unsupported version work?

Also, can someone offer a link to a how-to on ESXi 4.0 Embedded that I can do from Mac OSX? Isn't there some fanciness that I will have to do with the iso file or something like that? I've seen posts on how to install 3.5 to a flash drive, but an update for 4.0 would be better.