I am trying to debug a broken page in a Drupal application and am having a hard time getting PHP to spit anything useful out. I have the following set:

error_reporting = E_ALL
display_errors = On
display_startup_errors = On
log_errors = On
error_log = /var/log/php/php_error.log

I have a file showing me phpinfo() which confirms these variables are set correctly for the environment. I have increased memory_limit to 256M (which should be more than enough). Yet, the only indication I get is a status 500 code in the apache access log and a blank white page from PHP.

The Apache virtual host has LogLevel set to debug and the error log only outputs:

[Sat Jun 16 20:03:03 2012] [debug] mod_deflate.c(615): [client 173.8.175.217] Zlib: Compressed 0 to 2 : URL /index.php, referer: http://ec2-174-129-192-237.compute-1.amazonaws.com/admin/reports/updates
[Sat Jun 16 20:03:03 2012] [error] [client 173.8.175.217] File does not exist: /var/www/favicon.ico
[Sat Jun 16 20:03:03 2012] [debug] mod_deflate.c(615): [client 173.8.175.217] Zlib: Compressed 42 to 44 : URL /favicon.ico

The PHP error log outputs nothing at all. kernel and syslog show nothing related to Apache or PHP. I have also tried installing suphp and checking its log just confirms the user is executing correctly:

[Sat Jun 16 20:02:59 2012] [info] Executing "/var/www/index.php" as UID 1000, GID 1000
[Sat Jun 16 20:05:03 2012] [info] Executing "/var/www/index.php" as UID 1000, GID 1000

This is on Ubuntu 12.04 x86_64 with the following PHP modules:

ii  php5                             5.3.10-1ubuntu3.1          server-side, HTML-embedded scripting language (metapackage)
ii  php5-cgi                         5.3.10-1ubuntu3.1          server-side, HTML-embedded scripting language (CGI binary)
ii  php5-cli                         5.3.10-1ubuntu3.1          command-line interpreter for the php5 scripting language
ii  php5-common                      5.3.10-1ubuntu3.1          Common files for packages built from the php5 source
ii  php5-curl                        5.3.10-1ubuntu3.1          CURL module for php5
ii  php5-gd                          5.3.10-1ubuntu3.1          GD module for php5
ii  php5-mysql                       5.3.10-1ubuntu3.1          MySQL module for php5

So, what am I missing here? Why no error reporting?