This error generally indicates that the DHCP server has not provided either a filename or a root-path for iPXE to boot from.

Things to try:

• Use the iPXE command line to perform DHCP manually, and check that the correct filename and/or root-path are obtained from the DHCP server:
  

      iPXE> dhcp
      DHCP (net0 52:54:00:12:34:56)... ok
      iPXE> echo ${filename}
      wdsnbp.com
      iPXE> echo ${root-path}
      iscsi:192.168.0.1::::iqn.1991-05.com.microsoft:snubfin-win2k8

• Capture a packet trace showing the DHCP request from iPXE and the response from the DHCP server, and check that the correct filename and/or root-path are present in the response.

• If your DHCP server was previously configured to respond to a DHCP user class of “gPXE” then you will need to reconfigure it to respond to a DHCP user class of “iPXE” instead.