Mark has made a version of the bigdisk builder which will wipe a drive even if it's already built. This is "builder_bigdisk_v6.upgrade" which is available at http://rtr.ca/bigdisk/ . Use that first.

Next, don't use V3 alpha unless you absolutely have a need to play OGG and FLAC files. Instead, use car2_v2.01_hijack.upgrade, again found at http://rtr.ca/bigdisk/ .

After doing that, let us know how it goes.