This error indicates that your iPXE script has attempted to goto a non-existent label.

Things to try:

• Check the script line that defines the label, such as

      :my_label

• Check the script line that attempts to goto the label, such as

      goto my_label

  Note that the label name specified in the goto command must not include the colon (:) sign:

      # This is wrong
      goto :my_label

• If you are using a dynamically-generated label, such as

      goto host_${hostname}

  then you should consider using a fallback label in case the dynamically-generated label does not exist. For example:

      goto host_${hostname} || goto unknown