[SOLVED] Fatal error: require_once(): Failed opening required '/...../gallery2/modules/core/classes/Gallery.

Hi

I added a new site to my multi-site installation. I'm not sure what I did, but now it's not working. On the main site (and in the apache logs) I see the following:

Warning: require_once(/var/www/domains/example.net/photos/gallery2/modules/core/classes/Gallery.class): failed to open stream: Permission denied in /var/www/domains/example.net/photos/gallery2/bootstrap.inc on line 33

Fatal error: require_once(): Failed opening required '/var/www/domains/example.net/photos/gallery2/modules/core/classes/Gallery.class' (include_path='.:/usr/share/php:/usr/share/pear') in /var/www/domains/example.net/photos/gallery2/bootstrap.inc on line 33

I've googled this for several days and got nowhere. In an effort to fix this, I've even made Gallery.glass 777 - and I still get the error!
I've replaced bootstrap.inc and Gallery.class with the original files I unpacked and I still have no success.

Line 33 is:
29 if (!defined('GALLERY_FORM_VARIABLE_PREFIX')) {
30 define('GALLERY_FORM_VARIABLE_PREFIX', 'g2_');
31 }
32
33 require_once(dirname(__FILE__) . '/modules/core/classes/Gallery.class');
34 require_once(dirname(__FILE__) . '/modules/core/classes/GalleryDataCache.class');

As far as I remember, this is what I did immediately before the problem...
I updated Gallery to 2.3.2 from 2.3.1 - went OK
I added a new multi-site - went ok
I configured a bunch of modules - which seemed to have gone ok
I went to reconfigure to make the base install use https (I had the issue that apache was doing an https redirect by the css was still being served on http and some browsers were complaining about this - the new multi-site I managed to get working completely on https and I wanted to propogate the changes) - at this point I got the above error.

After that I wasn't able to able to access on the sites.

Any ideas? I can't figure out why I have a stream open access issue after I made the file 777 so I'm a little stumped. If it's a pear problem, why wasn't this an issue earlier in the day (I haven't made changes to pear or any modules in weeks).

Any help appreciated, thanks!

Gallery version (not just "2"): 2.3.2
PHP version (e.g. 5.1.6): 5.4.4-14+deb7u2
Webserver (e.g. Apache 1.3.33): 2.2.22-13
Database (e.g. MySql 5.0.32): 5.5.31+dfsg-0+wheezy1
Activated toolkits (e.g. NetPbm, GD): GD ffmpeg jpegtrans craw
Operating system (e.g. Linux): Debian 7.1
Browser (e.g. Firefox 2.0): Firefox 22, Chrome,