Mime type problem for rails+opera

I get the following behavior within rails
You have a nil object when you didn’t expect it!
The error occurred while evaluating nil.call

RAILS_ROOT: script/…/config/…
Application Trace | Framework Trace | Full Trace
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/mime_responds.rb:167:in
respond' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/mime_responds.rb:161:ineach’
/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/mime_responds.rb:161:in
respond' /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/actionpack-1.13.3/lib/action_controller/mime_responds.rb:105:inrespond_to’
app/controllers/schools_controller.rb:146:in `submit’

within the
respond_to do |format|
format.html
format.xml
end

call in a controller.
With opera–turns out opera requests something ‘non standard’ so the
mime types don’t handle it right.

(rdb:16) p priority
#<Mime::Type:0x21c1568 @synonyms=[“application/xhtml+xml”],
@string=“text/html”, @symbol=:degreematch>
(rdb:16) p @order
[#<Mime::Type:0x19fe1a0 @synonyms=[“application/xhtml+xml”],
@string=“text/html”, @symbol=:html>, #<Mime::Type:0x19fdf70
@synonyms=[“text/xml”, “application/x-xml”], @string=“application/xml”,
@symbol=:xml>]
(rdb:16) p priority === @order
true

Question: is this a rails bug? is === broken? Thanks!
-Roger