If you look closely, you'll note that c:/apache2/htdocs/onlinestore.com/production/cache/page_parse_time.log is a *filename*, not a directory.
The error message says "Warning: The sessions directory does not exist ...", as an attempt to provide a hint.
In Admin->Configuration->Sessions->Session Directory, you need to enter the path to a writable *directory*, not a filename.
Your second issue is directly related to the first.




