Sorted:

undefined method `simple_nested_form_for'-Collection of common programming errors

Devise: Unknown action, Could not find devise mapping for path “/accounts/sign_out”-Collection of common programming errors

undefined method `error_messages_for' for #<#<Class:0x3981390>:0x-Collection of common programming errors

Undefined method failure_app for nil:NilClass-Collection of common programming errors

Can a Yahoo mail address be used with the Incredimail program?-Collection of common programming errors

How to call set or get a Controller's config property from a view?-Collection of common programming errors

problem about object-oriented-analysis-Collection of common programming errors

Unknown column value in field list – community page-Collection of common programming errors

Varnish DAEMON_OPTS Options Errors-Collection of common programming errors

Compiler is able to find function without matching .h file is updated?-Collection of common programming errors