I just posted a slightly revised version of Netomata Config Generator (NCG), version 0.10.2. The only difference from the recently-released version 0.10.1 is a small change in which Ruby libraries we depend upon, because of a reorganization of one of the commonly-used Ruby libraries.
Basically, NCG makes heavy use of the Ruby Dictionary class, which used to be part of the Facets library; however, as of the recent Facets 2.9.0 release, the Dictionary class is no longer included in Facets, and you have to get it from the Ruby Hashery library instead.
If you've got a working NCG installation, this shouldn't affect you, unless you update your Ruby libraries so that you only have Facets 2.9.0 or later. A simple "gem update" to update your libraries would install the new version of Facets, but wouldn't delete the old version (unless you also did a "gem cleanup"), and Ruby will happily continue to take the Dictionary class from the older version of Facets if it's still there.
If you do break your NCG installation by updating Facets to 2.9.0 and then deleting the older version(s), it's easy to add the older version back simply by doing "gem install -v 2.8.4 facets". Your Ruby installation will prefer Facets 2.9.0, but will fall back to Facets 2.8.4 for stuff that it can't find in 2.9.0 (including the "Dictionary" class that NCG depends upon).
As always, the latest version of NCG can be downloaded from http://www.netomata.com/tools/ncg
Thanks to Bryan Wann for bringing this problem to our attention, and suggesting the fix.