Install Aegir stops at Loading apache driver for the http service

Hi :

When I install Aegir,it stops at "Loading apache driver for the http service". And no error and notice appears.
Just stop on this step.
Any help?

Executing: svn info /tmp/make_tmp_1356412135_50d934e73232f
sh: svn: command not found

Executing: bzr root /tmp/make_tmp_1356412135_50d934e73232fCalling [debug]
_drush_recursive_copy(/tmp/drush_tmp_1356412136_50d934e883c6f/__build__,
/tmp/make_tmp_1356412135_50d934e73232f/__build__) [48.78 sec, 9.93
MB]
sh: bzr: command not foundProject drupal (6.27) downloaded to [success]
/tmp/make_tmp_1356412135_50d934e73232f/__build__. [50.1 sec, 9.93 MB]
Project drupal contains: [success]
- 1 profile: default
- 6 themes: minnelli, garland, pushbutton, marvin, chameleon,
bluemarine
- 33 modules: search, poll, trigger, upload, throttle, color, help,
php, profile, system, blogapi, openid, filter, ping, update, dblog,
locale, path, book, contact, statistics, translation, user, tracker,
aggregator, syslog, block, taxonomy, blog, menu, node, forum, comment
[50.13 sec, 9.95 MB]
Command dispatch complete [50.14 sec, 9.87 MB] [notice]
Peak memory usage was 10.9 MB [50.14 sec, 9.87 MB] [memory]
drupal-6.27 downloaded. [50.33 sec, 9.84 MB] [ok]
Backend invoke: /usr/bin/php /drush/drush.php --php=/usr/bin/php [command]
--backend=2 --root= --uri= make-process
/tmp/make_tmp_1356412135_50d934e73232f 2>&1 [50.37 sec, 9.8 MB]
/usr/bin/php /drush/drush.php --php=/usr/bin/php --backend=2 --root= [notice]
--uri= make-process /tmp/make_tmp_1356412135_50d934e73232f 2>&1
[50.37 sec, 9.81 MB]
Bootstrap to phase 0. [50.62 sec, 9.19 MB] [bootstrap]
Bootstrap to phase 0. [50.64 sec, 9.19 MB] [bootstrap]
Found command: make-process (commandfile=make) [50.64 sec, 9.19 MB] [bootstrap]
Loading release_info engine. [50.65 sec, 9.2 MB] [notice]
Loaded alias @server_master from file [notice]
/var/aegir/.drush/server_master.alias.drushrc.php [50.71 sec, 9.38
MB]
Loading mysql driver for the db service [50.73 sec, 9.52 MB] [notice]
Loading apache driver for the http service [50.74 sec, 9.63 MB]