I am on 3.2.1, with sass-rails-3.2.4 and sass-3.1.15...
The documentation for the asset pipeline says:
asset-url(\"rails.png\", image) becomes url(/a
We just had the same problem and fixed it by explicitly requiring sprockets in the Gemfile (even though it's a dependency of ActionPack):
group :assets do gem 'sprockets' gem 'sass-rails', '~> 3.2.3' # ... end
I don't know why, but it works now. ;-)