Method "clear" of null can not be called

[bernhardpflug]

Hello,

first of all thanks for sharing your script. It seems to be exactly what I want for simple time tracking. I set up everthing like you explained in your readme. Unfortunately every time I run a command I always get the error message Method "clear" of null can not be called, even if I just copy the code from your files. An event in the calendar is created, but I get no lines in the spreadsheet.
Might it be a problem that I use the German language in Google Sheets?