The solution I found here you should just add acpi=off to your bootloader promt, as it is said in the vmware communities:
to enable installing ESX on HP Proliant DL160 G5 you should:
1. Press Tab on very first screen of ESXi install
2. Move cursor just after first tgz filename and write "acpi=off"
3. press Enter and ESXi successfully install on DL160G5
4. Be careful because after this setting is lost and problem appears again - solution:
a) disconnect HDD, connect to computer with Win XP (Marti: or another else!), then edit boot.cfg on second partition andin second line set "kernelopt=acpi=off"
b) after starting ESX go to console (Alt-F1, see also "usupported" mode and "enable SSH in ESX" topics) type vi /bootbank/boot.cfg and set "kernelopt=acpi=off"