/etc/xen/trixbox2.6.hvmの中身を示しておきます。
太字になっているところが、今回修正した部分です。

# -*- mode: python; -*-#============================================================================
# Python configuration setup for 'xm create'.# This script sets the parameters used when a domain is created using 'xm create'.# You use a separate script for each domain you want to create, or
# you can set the parameters for the domain on the xm command line.#============================================================================
import os, rearch = os.uname()[4]if re.search('64', arch):
arch_libdir = 'lib64'else: arch_libdir = 'lib'#----------------------------------------------------------------------------# Kernel image file.
kernel = "/usr/lib/xen/boot/hvmloader"
# The domain build function. HVM domain uses 'hvm'.
builder='hvm'

# Initial memory allocation (in megabytes) for the new domain.
## WARNING: Creating a domain with insufficient memory may cause out of
# memory errors. The domain needs enough memory to boot kernel# and modules. Allocating less than 32MBs is not recommended.memory = 768 # Shadow pagetable memory for the domain, in MB.# Should be at least 2KB per MB of domain memory, plus a few MB per vcpu.
# shadow_memory = 8
# A name for your domain. All domains must have different names.
name = "trixbox2.6"
#好きな名前を付けましょう。
# 128-bit UUID for the domain. The default behavior is to generate a new UUID
# on each call to 'xm create'.#uuid = "06ed00fe-1162-4fc4-b5d8-11993ee4a8b9"#-----------------------------------------------------------------------------
# The number of cpus guest platform has, default=1
vcpus=1

# Enable/disable HVM guest PAE, default=1 (enabled)
pae=1
#PAEで構築をずっとしていますので、PAE=1にします。
PAEは大容量のメモリを使える、という意味です。

# Enable/disable HVM guest ACPI, default=1 (enabled)
#acpi=1

# Enable/disable HVM APIC mode, default=1 (enabled)
# Note that this option is ignored if vcpus > 1
#apic=1

# List of which CPUS this domain is allowed to use, default Xen picks
#cpus = "" # leave to Xen to pick
#cpus = "0" # all vcpus run on CPU0
#cpus = "0-3,5,^1" # run on cpus 0,2,3,5
# Optionally define mac and/or bridge for the network interfaces.
# Random MACs are assigned if not given.
#vif = [ 'type=ioemu, mac=00:16:3e:00:00:50, bridge=xenbr0, model=ne2k_pci' ]
# type=ioemu specify the NIC is an ioemu device not netfront
vif = [ 'type=ioemu, bridge=xenbr0' ]
#ちなみにここは元のままですが、これは変えてはいけません。
#私はこれを変更してしまって、インストールが完了しない、
#というトラブルに見舞われました。
#----------------------------------------------------------------------------
# Define the disk devices you want the domain to have access to, and
# what you want them accessible as.
# Each disk entry is of the form phy:UNAME,DEV,MODE
# where UNAME is the device, DEV is the device name the domain will see,
# and MODE is r for read-only, w for read-write.
#disk = [ 'phy:hda1,hda1,r' ]
#disk = [ 'file:/var/images/min-el3-i386.img,hda,w', ',hdc:cdrom,r' ]
disk = [ 'file:/var/xen/images/trixbox2.6.img,hda,w' ]
#disk = [ 'file:/var/xen/images/trixbox2.6.img,sda1,w', 'file:/backup/trixbox-2.6.1.13-i386-DVD.iso,hdc:cdr
om,r,' ]
#ここが重要です。
#作成したイメージファイルを設定することと、
#/backupにダウンロードしたisoファイルのインストールメディアとして
#設定する必要があります。
#今回は、完全仮想化ですから、swapファイルの設定はしていません。
#インストールの最中に、仮想イメージの中に作成します。
#----------------------------------------------------------------------------
# Configure the behaviour when a domain exits. There are three 'reasons'
# for a domain to stop: poweroff, reboot, and crash. For each of these you
# may specify:
#
# "destroy", meaning that the domain is cleaned up as normal;
# "restart", meaning that a new domain is started in place of the old
# one;
# "preserve", meaning that no clean-up is done until the domain is
# manually destroyed (using xm destroy, for example); or
# "rename-restart", meaning that the old domain is not cleaned up, but is
# renamed and a new domain started in its place.
#
# The default is
#
# on_poweroff = 'destroy'
# on_reboot = 'restart'
# on_crash = 'restart'
#
# For backwards compatibility we also support the deprecated option restart
#
# restart = 'onreboot' means on_poweroff = 'destroy'
# on_reboot = 'restart'
# on_crash = 'destroy'
#
# restart = 'always' means on_poweroff = 'restart'
# on_reboot = 'restart'
# on_crash = 'restart'
#
# restart = 'never' means on_poweroff = 'destroy'
# on_reboot = 'destroy'
# on_crash = 'destroy'
#on_poweroff = 'destroy'
#on_reboot = 'restart'
#on_crash = 'restart'
#============================================================================
# New stuff
device_model = '/usr/' + arch_libdir + '/xen/bin/qemu-dm'
#-----------------------------------------------------------------------------
# boot on floppy (a), hard disk (c), Network (n) or CD-ROM (d)
# default: hard disk, cd-rom, floppy
boot="d"
#ここ重要です。
#インストールするには、インストールメディア（isoファイル）から
#インストールする必要がありますので、
#ここではboot="d"CDROMとします。
#ちなみに、上の設定でダウンロードしたisoファイルをCDROMとして
#設定してあります。

#-----------------------------------------------------------------------------
# write to temporary files instead of disk image files
#snapshot=1
#----------------------------------------------------------------------------
# enable SDL library for graphics, default = 0
sdl=1
#インストールするときに、vncはややこしいので、
#sdlを使います。
#用はGUIの仮想エミュレータをvncではなく、sdlを使う、というイメージです。
#----------------------------------------------------------------------------
# enable VNC library for graphics, default = 1
vnc=0
#vncは使わないように設定します。

#----------------------------------------------------------------------------
# address that should be listened on for the VNC server if vnc is set.
# default is to use 'vnc-listen' setting from /etc/xen/xend-config.sxp
#vnclisten="127.0.0.1"
#ここら辺もvncを使わないので必要ありません。
#----------------------------------------------------------------------------
# set VNC display number, default = domid
#vncdisplay=1
#上に同じで使いません。

#----------------------------------------------------------------------------
# try to find an unused port for the VNC server, default = 1
#vncunused=1
#----------------------------------------------------------------------------
# enable spawning vncviewer for domain's console
# (only valid when vnc=1), default = 0
#vncconsole=0

#----------------------------------------------------------------------------
# set password for domain's VNC console# default is depents on vncpasswd in xend-config.sxp#vncpasswd=''#----------------------------------------------------------------------------
# no graphics, use serial port
#nographic=0

#----------------------------------------------------------------------------
# enable stdvga, default = 0 (use cirrus logic device model)
stdvga=0
#-----------------------------------------------------------------------------
# serial port re-direct to pty deivce, /dev/pts/n
# then xm console or minicom can connect
serial='pty'

#-----------------------------------------------------------------------------
# Qemu Monitor, default is disable
# Use ctrl-alt-2 to connect
#monitor=1

#-----------------------------------------------------------------------------
# enable sound card support, [sb16|es1370|all|..,..], default none
#soundhw='sb16'

#-----------------------------------------------------------------------------
# set the real time clock to local time [default=0 i.e. set to utc]
#localtime=1
#-----------------------------------------------------------------------------
# set the real time clock offset in seconds [default=0 i.e. same as dom0]
#rtc_timeoffset=3600

#-----------------------------------------------------------------------------
# start in full screen
#full-screen=1
#-----------------------------------------------------------------------------
# Enable USB support (specific devices specified at runtime through the
# monitor window)
#usb=1

# Enable USB mouse support (only enable one of the following, `mouse' for
# PS/2 protocol relative mouse, `tablet' for
# absolute mouse)
#usbdevice='mouse'
#usbdevice='tablet'

#-----------------------------------------------------------------------------
# Set keyboard layout, default is en-us keyboard.
keymap='ja'
#意味があるか分かりませんが、キーボードのタイプを設定しておきます。

これで設定ファイルは以上です。