IDE will not work in ESX 4.0. You can also edit the descriptor virtual disk rather than perform the p2v again. You would do the following:
- Remove the virtual disk from the VM
- Edit the descriptor vmdk with a text editor
- Change the ide entry to buslogic, save and exit
- Add the virtual disk back to the VM
- Verify that the scsi controller is set to buslogic
- Power on the VM and it should boot