The installer of Tcl/Tk for each platform can be obtained from the Activestate web site (www.activestate.com).
Though versions of 8.4, 8.5 and 8.6 are provided at the time of preparation of this document,it is preferable to use the version 8.4 or 8.5 because tkDerm isn't tested on Tcl/Tk 8.6.