The calendar.pl and calendar_admin.pl files should only need to be chmod to 755. The rest of the files and directories should need at most 666 or 766 depending. (755 *might* work too depending on the server set up)
On all the servers I've set CalendarScript up on, none even needed file permissions set besides just for the calendar.pl and calendar_admin.pl files. BTW. I always transfer the files to the host using FTP and not the supplied batch file.
JFYI
Dan O.
[This message has been edited by DanO (edited June 02, 2005).]