I'm not sure if this is the right place, but anyway... The topic says it all it seems it wants to create $PORTAGE_OVERLAY/<cat>/foobar/foobar-0.0.1.ebuild which fails badly for me due to the fact that i have PORTDIR_OVERLAY="/usr/local/portage /usr/local/portrepair /usr/local/overlays/bmg-main"
Since this isn't an official Gentoo utility it'd be better if you reported it on Abeni's website, but no problem. Its looking for a ':' as the delimiter, which should be a space. You can take a look in the source code for it and change it, or wait for 0.0.10 which hopefully will be out next week.