Joyce, could you please start the installer with 'ubiquity -d' from a terminal window, and reproduce this problem (just reproducing the first problem you ran into will be fine - all I need is for you to get to the point where it says "ubi-partman failed with exit code 141", then exit the installer)? Once you've done that, please attach /var/log/syslog, /var/log/partman, and /var/log/installer/debug to this bug report. It's important that you attach all those files.
Joyce, could you please start the installer with 'ubiquity -d' from a terminal window, and reproduce this problem (just reproducing the first problem you ran into will be fine - all I need is for you to get to the point where it says "ubi-partman failed with exit code 141", then exit the installer)? Once you've done that, please attach /var/log/syslog, /var/log/partman, and /var/log/ installer/ debug to this bug report. It's important that you attach all those files.