In http://groups.google.com/groups?&selm=140420031230180763%25steffen%40ics.mq.edu.au&rnum=1 Daniel Steffen said that the difference in how it works is that one needs X11 installed for Tk to work with http://www.equi4.com/pub/tk/8.4.2/tclkit-darwin-ppc.gz .
I can't comment on the darwin 8.4.2 version, but have tried sdx under an earlier version of tclkit (2002-11-22) with MacOS 9.x. The sdx kit was not initially useful, but with the addition of an entry widget for command line arguments (Thanks Mr. Whippler!) and a few hacks to 'file' commands (in my local copy only) I have been able to use 'qwrap', 'wrap' and 'unwrap'.