Failed to open or unlink config_autoload.yml.php warning

[yuelu]

I see a few of the following warnings in my apache log daily. Any idea what may be causing this? Thanks

[Mon May 28 04:28:09 2012] [error] [client 198.228.212.19] PHP Warning: include(): Failed opening '/var/cache/my-project/device/dev/config/config_autoload.yml.php' for inclusion (include_path='.:/usr/share/php:/usr/share/pear:/usr/share/my-project/lib/mdm:/usr/share/my-project/lib/vendor') in /usr/share/my-project/lib/vendor/symfony/lib/autoload/sfAutoload.class.php on line 138

[Wed May 30 13:28:41 2012] [error] [client 198.228.213.26] PHP Warning: unlink(/var/cache/my-project/device/dev/config/config_autoload.yml.php): No such file or directory in /usr/share/my-project/lib/vendor/symfony/lib/autoload/sfAutoload.class.php on line 132

[j0k3r]

Same problem here. I've no idea why.
It mostly happen from task, at least I can see error from task about that.