Didn't mean to close.

Upgrading my server environment to PHP 5.4 made the error disappear. Running Symfony 2.1 and 1.1.*@dev.

Same problem here but already in 5.4 (Symfony 2.3)

Same problem with PHP 5.4 Symfony 2.2, and setting the config file still didn't solve the problem.

I cleared my cache files manually and it fixed the problem.

I stopped having problems once I was using Symfony 2.1 and PHP 5.4. Before that I noticed that clearing the cache manually fixed my problem locally. When I deployed my application I had the error again when running my deploy hooks. You might want to check for that.

This has been fixed by 2a15188

If you face it by any chance, just delete the cache directory manually.

This error still exists in symfony 2.5 and PHP 5.5.13

I can second @pats on that. I'm having this with Symfony 2.5 & PHP 5.5

👍 Also just had this error,

I just get this error. (Symfony 2.5, PHP 5.5) But delete the cache directory seems to solve the problem.

Deleting cache dir manually did the trick (Symfony 2.5, PHP 5.5).

Deleting the cache manually worked for me too.
(Symfony 2.6, php 5.4.35)

yes, this does the trick! manually clean the cache dir

I also get this error with Symfony 2.5 and PHP 5.5.9, clearing cache folder manually fixes it, but actually this is not a proper solution.

Symfony 2.6.5, PHP 5.5.20 with OpCache 7.0.4 and Xdebug 2.2.3, OS X 10.10.3 still has this problem in production but not dev environment

delete the cache manually worked for me thanks a lot