Calibre Server comes with Calibre - there is no Apache installation necessary (yeah, I do realise that it's meant as a workaround).
(Furthermore, making Calibre point its library to a network share is not advisable. But, well, I do it, so... Yeah.)
So anyways, try to put your library back on your local drive, and see if the Internal Server error on
http://192.168.0.202:8080 still occurs.
Note that what you're trying to do with Apache is serving a filesystem with no index file at its root, so you'd have to add an Options Indexes directive (I think? It's been a while since I needed that one), preferably in an .htaccess file in the library root.
N.