The ebuilds for both versions of dev-lang/smlnj contain incorrect SRC_URI definitions. mirror://file-name is invalid, and should be changed to mirror://gentoo/file-name. In case this regards a change in Portage, I am using Portage 2.0.51_pre20.
I can confirm this bug.
Yes it is, hopefully this *bump* will put things into motion.
Fixed in CVS !