Failed to download snapshot errors, downloads never complete

[fadookie]

I have tried to use this tool to download several snapshots from us-west-1. The download progress bars get very far along, I have not seen if it reaches the end but they always error out, even on different snapshots:

eliot@mac ebs_coldsnap % coldsnap download snap-0cdb361111a7203b1 minecraft_engineering_server_snap-0cdb361111a7203b1.img
Failed to download snapshot: Failed to get 1 blocks for snapshot 'snap-0cdb361111a7203b1': Failed to find data for block 4776 in 'snap-0cdb361111a7203b1'

eliot@mac ebs_coldsnap % coldsnap download snap-0cdb361111a7203b1 minecraft_engineering_server_snap-0cdb361111a7203b1.img
Failed to download snapshot: Failed to get 6 blocks for snapshot 'snap-0cdb361111a7203b1': Failed to find data for block 1058 in 'snap-0cdb361111a7203b1'Failed to find data for block 1099 in 'snap-0cdb361111a7203b1'Failed to find data for block 1193 in 'snap-0cdb361111a7203b1'Failed to find data for block 4185 in 'snap-0cdb361111a7203b1'Failed to find data for block 4705 in 'snap-0cdb361111a7203b1'Failed to find data for block 5103 in 'snap-0cdb361111a7203b1'

eliot@mac ebs_coldsnap % coldsnap download snap-0986116135cc7d76b minecraft_engineering_server_post_zombie_survival_snap-0986116135cc7d76b.img
Failed to download snapshot: Failed to get 6 blocks for snapshot 'snap-0986116135cc7d76b': Failed to find data for block 5179 in 'snap-0986116135cc7d76b'Failed to find data for block 5803 in 'snap-0986116135cc7d76b'Failed to find data for block 8375 in 'snap-0986116135cc7d76b'Failed to find data for block 8632 in 'snap-0986116135cc7d76b'Failed to find data for block 12702 in 'snap-0986116135cc7d76b'Failed to find data for block 13261 in 'snap-0986116135cc7d76b'

eliot@mac ebs_coldsnap % SNAP_ID='snap-03b6c769'; coldsnap download $SNAP_ID "maybe_git_server_$SNAP_ID.img"
Failed to download snapshot: Failed to get 12 blocks for snapshot 'snap-03b6c769': Failed to find data for block 254 in 'snap-03b6c769'Failed to find data for block 942 in 'snap-03b6c769'Failed to find data for block 3436 in 'snap-03b6c769'Failed to find data for block 3507 in 'snap-03b6c769'Failed to find data for block 8566 in 'snap-03b6c769'Failed to find data for block 19456 in 'snap-03b6c769'Failed to find data for block 19673 in 'snap-03b6c769'Failed to find data for block 19700 in 'snap-03b6c769'Failed to find data for block 24017 in 'snap-03b6c769'Failed to find data for block 24139 in 'snap-03b6c769'Failed to find data for block 24690 in 'snap-03b6c769'Failed to find data for block 26910 in 'snap-03b6c769'

eliot@mac ebs_coldsnap % SNAP_ID=snap-43470d29; coldsnap download $SNAP_ID "git_server_$SNAP_ID.img"
Failed to download snapshot: Failed to get 10 blocks for snapshot 'snap-43470d29': Failed to find data for block 35 in 'snap-43470d29'Failed to find data for block 49 in 'snap-43470d29'Failed to find data for block 779 in 'snap-43470d29'Failed to find data for block 1805 in 'snap-43470d29'Failed to find data for block 3594 in 'snap-43470d29'Failed to find data for block 7685 in 'snap-43470d29'Failed to find data for block 21094 in 'snap-43470d29'Failed to find data for block 24943 in 'snap-43470d29'Failed to find data for block 27063 in 'snap-43470d29'Failed to find data for block 27320 in 'snap-43470d29'

The snapshot sizes of the ones I've tried so far have been around 3GB, with an 8-15 GB volume size.