_tkinter.TclError: Can't find a usable tk.tcl in the following directories:
/usr/local/lib/tcl8.6/tk8.6 /usr/local/lib/tk8.6 /usr/lib/tk8.6 /usr/lib/tk8.6 /lib/tk8.6 /usr/library

After installation, make sure that the directory containing the installed executables (ActiveTcl/bin) is included in your PATH variable.
   export PATH="/opt/ActiveTcl-8.6/bin:$PATH"
You can also add the man directory to your path to access the man page documentation on the command line.
   export PATH="/opt/ActiveTcl-8.6/man:$PATH"