It seems unusual to me that you would have a Calendar.ss in /mysite/templates/Layout if you haven't made any changes. Does Calendar.ss exist in /event_calendar/templates/Layout, as well? Are there any templates in /event_calendar/templates?
yes i have Calendar.ss in event_calendar/templates/Layout and in event_calendar/templates/
i have copie one of this Calendar.ss in /mysite/template/Layout
Wow. I'm sorry, I have absolutely no idea what could be going on. It sounds like something is not in the right place in the filesystem. The only thing I can suggest is if you could give me read-only FTP access, I can take a look, but otherwise, I'm completely puzzled.
i can't give you access on ftp ..
I recheck my code...