Upgrade Rails 2 -> 3: Can't convert Symbol into String

I have troubles with upgrading my rails app from 2 to 3. I'm using the following gems:

gem 'rails', '3.0.3'
gem 'rbrainz'
gem 'amatch'
gem 'warden'
gem 'devise'
gem 'gravtastic', '>= 2.1.0'
gem 'redis'
gem "newrelic_rpm"
gem 'hoptoad_notifier'
gem 'will_paginate'
gem 'capistrano'

I'm using devise for the user management. When I'm adding

map.devise_for :users

into the routes.rb, I'm getting the following error while starting rails s:

/Users/MyUser/.rvm/gems/ruby-1.9.2-开发者_StackOverflow社区p136@rails3/gems/rack-mount-0.6.13/lib/rack/mount/strexp/tokenizer.rb:18:in `initialize': can't convert Symbol into String (TypeError)

I don't know if this is devise's fault, but I guess it. I'm using the current version 1.1.5 of devise. It should work with Rails 3. But what is rack-mount?

Hope anybody can help.

thx, tux

In Rails 3 routes files you don't need to use the map. prefix. Just

devise_for :users

Will do the trick.