Watir::Exception::MissingWayOfFindingObjectException: css is an unknown way of finding a <*> element (option)
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:125:in `rescue in match?'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:122:in `match?'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:32:in `block in match_with_specifiers?'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:32:in `each'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:32:in `all?'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:32:in `match_with_specifiers?'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:102:in `block in each'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:96:in `block in each_element'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:95:in `each'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:95:in `each_element'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/locator.rb:101:in `each'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/collections.rb:22:in `each'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/element_collections.rb:25:in `length'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/element_collections.rb:19:in `initialize'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/html_element.rb:26:in `new'
from C:/Ruby192/lib/ruby/gems/1.9.1/gems/watir-2.0.2/lib/watir/html_element.rb:26:in `elements'
from (irb):23
from C:/Ruby192/bin/irb:12:in `<main>'
Fixed in https://github.com/bret/watir/commit/0d56ca56c88643e6e6350d91fac73b1baf247dd1