[pmwiki-users] WikiGallery (was: Free thoughts on images)

[kirpi at kirpi.it]

While installing, I get:

Warning: main(/web/htdocs/www.kirpi.it/home/wiki/cookbook/wikigallery/wikigallery.php)
[function.main]: failed to open stream: No such file or directory in
/web/htdocs/www.kirpi.it/home/wiki/local/config.php on line 244

Warning: main() [function.include]: Failed opening
'/web/htdocs/www.kirpi.it/home/wiki/cookbook/wikigallery/wikigallery.php'
for inclusion (include_path='.:/php/lib/php/') in
/web/htdocs/www.kirpi.it/home/wiki/local/config.php on line 244

Fatal error: Cannot instantiate non-existent class: gallerypagestore
in /web/htdocs/www.kirpi.it/home/wiki/local/config.php on line 245

The incriminated lines are:
include_once("$FarmD/cookbook/wikigallery/wikigallery.php");
$WikiLibDirs[] = new GalleryPageStore('Pics');

I tried to follow the instructions, but something is not clear; it says:

"Create the cache directory (below the directory where your pmwiki.php
is) and the same for the pictures directory. The former must be
writable by the webserver."

What does "writable by the webserver" mean? It is a way to express
some particular permissions? Is so, which? Otherwise, how will I make
sure that the /pictures/ directory is "writable by the webserver"?

Also, what about the permissions of the directories below /pictures/?

More in general, does anybody has an idea of the problem, please?

Thank you
Luigi