[SOLVED] Cannot install. Every gallery page instantly fails with 500 error - other php is OK

Gallery version (not just "2"): Latest stable release as of 1 hour ago (2.3.1?)
PHP version (e.g. 5.1.6): 5.2.9
PHPInfo Link (see FAQ): <removed>
Webserver (e.g. Apache 1.3.33): Apache 2.2.11
Database (e.g. MySql 5.0.32): MySQL
Activated toolkits (e.g. NetPbm, GD): n/a
Operating system (e.g. Linux): Linux
Browser (e.g. Firefox 2.0): Opera 10.10

Just installed Gallery via the preinstaller. The download and extraction steps went like a dream. Because I am replicating an installation on another web server, I renamed my installation folder from "gallery2" to "photos" (I've since tried renaming it back and no difference).

However, I cannot run any of the gallery php pages. Not even the installer. Every single one gives a 500 error. I thought maybe this was a permissions issue, so I changed everything recursively to 777. Still no joy. phpinfo says memory limit is 64M which seems pretty generous, so I don't think I have the low memory issue.

This is baffling because I installed another package (phpBB3) yesterday, and had no problems. The preinstaller runs just fine, as does all the php inside my other packages.

Because this is a new host to me, I'm not sure if I have access to the webserver logs. I will check later (I can't run the cpanel at work because it uses a blocked port).

In the meantime, does anybody have any suggestions?

Thanks

Nick

Fixed. My host has a check in Apache that checks if files are writable by others and refuses to serve them if they are. I had to use 755, not 777. Left in case it helps others.

Nick