I have tried installing BT3 a few times and it always fails when I try to use multiple partitions and or reiserfs on root.

/dev/hda1 50MB /boot
/dev/hda2 2048MB Swap
/dev/hda3 Logical Drive
/dev/hda5 20GB /
/dev/hda6 60GB /home

hda5 => /mnt/int/ - reiserfs
hda1 => /mnt/int//boot - ext2
hda6 => /mnt/int//home -reiserfs

Started installer, installer detected the correct settings (install to /mnt/int)
Changed Install method to Real

Started 11:37

It is now 12:06, the installer has been on 100% for the last 5 minutes. The button still says wait and the installer still says copying /var

df -h reports
2.9G /mnt/int
33M /mnt/int/home
878K /mnt/int/boot

- I managed to install BT3 with the following layout hda1 as root ext3 and hda2 as swap