There is no separate "nstdom" module, there is just tDOM. Since tDOM is not primarily an AOLserver module it probably doesn't belong in the AOLserver CVS repository. The AOLserver "module" part of tDOM is basically a trivial Ns_ModuleInit that gets included if you configure with --with-aolserver before building. (Not necessary for AOLserver 4.)
We could do the comprehensive tarball thing as Don suggests and ask that it be added to the AOLserver file download section on SourceForge. Or we could upload some "known good" tarballs of things like tDOM so new users can just grab all of the needed pieces from one place. That way we would also take advantage of the SourceForge bandwidth and mirroring system.
In other AOLserver chat news, 4.0 beta 3 is coming soon, probably tomorrow, and in addition to several bugfixes, it is supposed to have the remaining AD13 i18n features. (That code has been checked in, but I haven't looked at it yet.) In addition, a first draft of a module author upgrade guide was announced, and we discussed issues related to cataloguing and cleaning up non-core modules of various types. The complete text of the chat is at http://empoweringminds.mle.ie/openacs/chatlog/today.html