This is an odd bug that I did not expect to run into. I have been unable to trace it so far (due to time, not technical difficulty) but it seems that something in the patchset for snns-4.2-r9 (ie "SNNS 4.2 DAN") renders it unable to parse and load .net files that were generated in and still work perfectly fine in earlier versions. This incompatibility, for me, makes the package rather useless unfortunately and I've had to mask this particular revision. Note that the source files are coming from an unofficial sourceforge repository rather than the official upstream location at http://www.ra.cs.uni-tuebingen.de/ ; it may be pertinent to, instead of using this tarball on sourceforge, use the official source release for 4.2 (or 4.3) and install all patches off of that as a patchset.
+*snns-4.3-r1 (10 Apr 2015) + + 10 Apr 2015; Ian Stakenvicius (_AxS_) <axs@gentoo.org> +snns-4.3-r1.ebuild, + +files/4.3-bison-version.patch, +files/4.3-unstrip.patch, metadata.xml: + Took over package maintainership and restored 4.3 version to the tree with + nod from xarthisius. 4.3-r1 ebuild resolves file parsing bug introduced in + 4.2-r9 (bug 546066) and converts to distutils-r1 (bug 544920). +