I have this error in my server and I'm not sure why this is happening and how can I solve it.

InvalidArgumentException: [ERROR 3070] complex type 'service': The content model is not determinist. (in file:////home/serraeng/serraeng/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/schema/dic/services/services-1.0.xsd - line 75, column 0)
[ERROR 3070] complex type 'argument': The content model is not determinist. (in file:////home/serraeng/serraeng/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/schema/dic/services/services-1.0.xsd - line 131, column 0)
[ERROR 3070] complex type 'call': The content model is not determinist. (in file:////home/serraeng/serraeng/vendor/symfony/symfony/src/Symfony/Component/DependencyInjection/Loader/schema/dic/services/services-1.0.xsd - line 144, column 0)

You can also see it online here: http://serraengineering.info/app_dev.php/

This is not a Symfony related issue, I'm just looking any tips on how to fix this.
Thanks in advance.