I've got a symfony 1.4 project that's constantly putting the next warning within the Apache error log:

[Wed Sep 26 06:18:22 2011] [error] [client 192.168.100.12] PHP Warning: unlink(/var/cache/project-ttp/device/dev/config/config_autoload.yml.php): No such file or directory in /usr/share/project-ttp/lib/vendor/symfony/lib/autoload/sfAutoload.class.php on line 132

Any idea what might be leading to this?