Q: So you've got an .iso image of VMWare ESXi Server 4.0, correct?
Q: And you've also configured your Linux host as a PXE server, correct?
Q: Have you mounted your .iso file as a loopback filesystem, per this link:
Q: Have you followed the rest of instructions
to copy the relevant files from your .iso to your PXE "sandbox"?
Q: Are *any* files being copied over from the PXE/TFTP server?
Q: What specific error messages are you gettinging?
Please provide as many details as you can.