I just installed Komodo 10.2 and tried to debug an old TCL script. Upon attempting to start the debugger I would get a “Debugging session has ended” message immediately.
I found the problem. If you open the c:\windows\syswow64\cmd.exe and enter wish or tclsh you will probably get an “access denied” error.
Somewhere, in my path there is another wish executable (sitting in one of the many EDA vendor tool installations probably) that does not want to run.
I moved c:\tcl\bin to the front of my PATH and now komodo starts the debugger properly.
Apparently, komodo is unable to tell that the cmd.exe did not execute the interpreter correctly so the debugger returns immediately that the session is finished.