Redmine

I've configured Redmine 1.3 und Debian 6. If I want to access redmine I get following error in the browser:

Error message:
syntax error on line 5, col 2: ` host: localhost'

Exception class:
ArgumentError

Application root:
/mnt/data/www/redmine-1.3

RAILS_ENV=production script/about tells:

/usr/lib/ruby/1.8/yaml.rb:133:in `load': syntax error on line 5, col 2: `  host: localhost' (ArgumentError)
    from /usr/lib/ruby/1.8/yaml.rb:133:in `load'
    from /var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:926:in `database_configuration'
    from /var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:437:in `initialize_database'
    from /var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:141:in `process'
    from /var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:113:in `send'
    from /var/lib/gems/1.8/gems/rails-2.3.14/lib/initializer.rb:113:in `run'
    from /mnt/data/www/redmine-1.3/config/environment.rb:24
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
    from /var/lib/gems/1.8/gems/rails-2.3.14/lib/commands/about.rb:1
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require'
    from /usr/lib/ruby/1.8/rubygems/custom_require.rb:31:in `require'
    from script/about:4

How can I solve this?