Symfony 2.1 – Uncaught PHP Exception Twig_Error_Runtime-Collection of common programming errors

This Exception is thrown in the dev environment if the profiler is enabled but it’s routing configuration is missing.

Unable to generate a URL for the named route "_wdt" as such route does not exist.

Please check that your app/config/routing_dev.yml contains the following lines:

# app/config/routing_dev.yml

_wdt:
    resource: "@WebProfilerBundle/Resources/config/routing/wdt.xml"
    prefix:   /_wdt

_profiler:
    resource: "@WebProfilerBundle/Resources/config/routing/profiler.xml"
    prefix:   /_profiler

This will fix your issue.