Thanks for updating your Texinfo, but doing that does not necessarily update texinfo.tex. And apparently it did not in your case -- at least, that would explain why the command is not defined.
To repeat, please try getting the current version from http://ftpmirror.gnu.org/texinfo/texinfo.tex. You can put in the directory with the document. pdftex, pdfetex, and pdfetexk are all the same thing. This is pdfeTeXk, Version 3.141592-1.21a-2.2 (Web2C 7.5.4) It has nothing to do with the problem, but that is almost ten years old. Pretty impressive :). Best, Karl
