ubuntu feisty 7.04 herd1 fails at installation

I just installed at last partition in the primary disk

{win | data | free space (8 megas) | swap | this was supposed to be '/' }

Here is the crash warning:

Traceback (most recent call last):
  File "/usr/bin/ubiquity", line 166, in ?
    main()
  File "/usr/bin/ubiquity", line 161, in main
    install(sys.argv[1])
  File "/usr/bin/ubiquity", line 57, in install
    ret = wizard.run()
  File "/usr/lib/ubiquity/ubiquity/frontend/gtkui.py", line 299, in run
    self.process_step()
  File "/usr/lib/ubiquity/ubiquity/frontend/gtkui.py", line 854, in process_step
    self.progress_loop()
  File "/usr/lib/ubiquity/ubiquity/frontend/gtkui.py", line 626, in progress_loop
    raise RuntimeError, ("Install failed with exit code %s\n%s" %
RuntimeError: Install failed with exit code 1
Traceback (most recent call last):
  File "/usr/share/ubiquity/install.py", line 1421, in ?
    install.run()
  File "/usr/share/ubiquity/install.py", line 355, in run
    self.install_language_packs()
  File "/usr/share/ubiquity/install.py", line 849, in install_language_packs
    self.mark_install(cache, lp)
  File "/usr/share/ubiquity/install.py", line 776, in mark_install
    assert cache._depcache.BrokenCount == 0
AssertionError

I'm using an ASROCK AM2NF6G-VSTA motherboard, an Athlon 64 +3200 at 2 GHz.

--

Also, when booting from liveCD, the loading image is displayed all in b/w. After logging in, when I scroll down in a web browser, it really takes much time to make a little scroll. I'm using a NVidia GeForce 7300 GS, but maybe Ubuntu is trying to use the integrated graphic card...