If you get that error you are probably trying to run SAVESELECTION c:\list.txt from the command line - that is not possible. SAVESELECTION and the other "Commands with parameters" can not be run from the command line, but has to be used in a button or in an em_command.B_ "SAVESELECTION c:\list.txt" doe snot work at all, "File not found!" error. Don't understand where is the typica "cm_" in this execution..
Also notice as Horst.Epp wrote - you cannot write to c:\list.txt (or other files in the root of c:) without running TC with administrator rights - but trying to do so without administrator rights does not cause an error message - it just silently fails.