Problem connecting to Oracle

[Andrew Cane]

require 'yaml'
require 'sequel'

    @db = Sequel.connect(:adapter=>'oracle',:user=>'user1', :password=>'password',:database=>'testing')

the above code gave me an error :
C:/test/Ruby/Ruby193/lib/ruby/site_ruby/1.9.1/rubygems/custom_require.rb:36:in
`initialize': wrong number of arguments (2 for 0..1) (ArgumentError)

I've tried the connection string using above credentials with sqlplus with no problem at all.
Can anybody tell me what's causing this error?
thanks

[Sumit Bisht]

Could you verify whether you are using the oracle instant client (http://www.oracle.com/technetwork/database/features/instant-client/index-097480.html).
It is required as it contains the dlls which are referenced by the ruby application.