try to deal with out-of-memory more gracefully?

Reporting on behalf of Popolon (see bug #54815 ):

I install Ubuntu but the installer crashed with error
We're sorry; the installer crashed. Please file a bug report at https://launchpad.net/distros/ubuntu/+source/ubiquity/+filebug and a developer will attend to the problem as soon as possible. To help the developers understand what went wrong, include the following detail in your bug report, and attach the files /var/log/installer/syslog, /var/log/syslog, and /var/log/partman:
Traceback (most recent call last):
  File "/usr/bin/ubiquity", line 130, in ?
    install(sys.argv[1])
  File "/usr/bin/ubiquity", line 55, in install
    ret = wizard.run()
  File "/usr/lib/python2.4/site-packages/ubiquity/frontend/gtkui.py", line 266, in run
    self.process_step()
  File "/usr/lib/python2.4/site-packages/ubiquity/frontend/gtkui.py", line 741, in process_step
    self.mountpoints_to_summary()
  File "/usr/lib/python2.4/site-packages/ubiquity/frontend/gtkui.py", line 1029, in mountpoints_to_summary
    self.progress_loop()
  File "/usr/lib/python2.4/site-packages/ubiquity/frontend/gtkui.py", line 538, in progress_loop
    raise RuntimeError, ("Install failed with exit code %s; see "
RuntimeError: Install failed with exit code 1; see /var/log/installer/syslog and /var/log/syslog

I just have the bug with a 128Mb computer

I made an about 512Mo swap partition (ubunutu unusable (toooooo slow, doesn't finished booting after half hour) without hard drive swap partition on this computer).