Number 1: like he said, check the $LFS variable
if the output is not
Number 2: I think the sources folder on the disk is "/lfs-sources" not "/sources"
and, just to copy the contents of the folder, not the folder itself, (it might annoy you later), type these commands EXACTLY:
chmod -v a+wt $LFS/sources
cp -r /lfs-sources/* $LFS/sources
that should do it.