More than one parameter in URL

Hello.

I'm trying to make my site work with OAI-PMH (http://
oai.rubyforge.org/). Whilst running the tests on http://re.cs.uct.ac.za/
it seems that it can't process more than two parameters. For example:

http://mysite.com/oai?verb=Identify works fine, but
http://mysite.com/oai?verb=Identify&test=tes end ups with an error
with any second parameter

Processing OaiController#index (for 0.0.0.0:3030 at 2010-01-09
00:47:21) [GET]
  Parameters: {"verb"=>"Identify", "test"=>"tes"}

TypeError (can't convert nil into Array):
  oai (0.0.12) lib/oai/provider/response.rb:67:in `-'
  oai (0.0.12) lib/oai/provider/response.rb:67:in `valid?'
  oai (0.0.12) lib/oai/provider/response.rb:31:in `initialize'
  ...

Line 67 is: return false unless (@options.keys -
self.class.valid_options).empty?
where, ofcourse, self.class.valid_options is nil. But why?
Any thoughts?