When i try to run Task Coach with my Greek locale i get no output in Task Window and in log file i get "File "taskcoachlib\render.pyo", line 133, in <lambda> UnicodeDecodeError: 'ascii' codec can't decode byte 0xec in position 5: ordinal not in range(128)" because of the date/time format with Unicode Characters </lambda>
Question: what happens if you make a new task viewer with the New menu?
Are you sure you're using 1.3.20 ? This should have been fixed... How should be the dates displayed in your locale ?