Same here, installed from within Leo.

Lots of random Kernel Panics in Snow. Got that fixed with rebuilding kextcache in single user boot.
I'm reinstalling BSD.pkg now to check if the "no packages" issue is gone.

Here's what I did to remove KP's:

boot with -s

/sbin/fsck -fy
/sbin/mount -uw /
sudo -s (dunno if this is necessary)
chown -R root:wheel /Volumes/snow partition/System/Library/Extensions/*
chmod -R 755 /Volumes/snow partition/System/Library/Extensions/*

then i did:

sudo chown 0:0 /
rm -rf /System/Library/Cashes
kextcache -v l -t -l -m /System/Library/Cahces/com.apple.kext.caches/Startup/Extensions.mkext /System/Library/Extensions

after a reboot I'm still in Snow whereas normaly it would have KP by now.