libwnck, provided by meta-gnome, has a fetch failure: ERROR: Fetcher failure: Fetch command failed with exit code 8, output: http://ftp.gnome.org/pub/GNOME/sources/libwnck/2.30/libwnck-2.30.5.tar.xz: 2015-09-04 17:43:57 ERROR 404: Not Found. And if you look at the web resource, it really does not exist. The one that seems to exist is a .tar.bz2
libwnck is not part of oe-core. It is part of meta-oe/meta-gnome but even that was upgraded to 2.31 in July. It sounds like you are using a fresh oe-core (which has a new default gnome compression format) and an older meta-gnome (which has a wnck release that isn't available in the new format). Upgrading meta-gnome should help.