Having the same issue. Please patch when you can. Thanks.

reproduced with
Windows XP SP3 32bits

using environement below

$ uname -a
CYGWIN_NT-5.1 mtb-p1247630 1.7.6(0.230/5/3) 2010-08-16 16:06 i686 Cygwin

$ ruby -v
ruby 1.8.7 (2008-08-11 patchlevel 72) [i386-cygwin]

$ gem list

• • • LOCAL GEMS ***

activesupport (2.3.8)
builder (2.1.2)
color (1.4.1)
commonwatir (1.6.5)
fastercsv (1.5.3)
firewatir (1.6.5)
hoe (2.6.1)
json_pure (1.4.3)
nokogiri (1.4.3.1)
pdf-writer (1.1.8)
rake (0.8.7)
rcov (0.9.8)
rspec (1.3.0)
rubyforge (2.0.4)
ruport (1.6.3)
s4t-utils (1.0.4)
transaction-simple (1.4.0)
user-choices (1.1.6.1)
watir (1.6.5)
win32-api (1.4.6)
win32-process (0.6.2)
windows-api (0.4.0)
windows-pr (1.0.9)
wirble (0.1.3)
xml-simple (1.0.12)

thanks andy, your suggestion worked !

so

1. replace the win32ole.so file so it matches the default ruby one

2. add the : unless RUBY_PLATFORM == 'i386-cygwin'
at File - win32.rb Line - 6 GetUnknown = Win32API.new(...

and the default Watir example works

(didn't need the other line update, maybe it will resurface later when i more seriously use watir)

watir team : please run tests on cygwin too

I have a completely different question which is not directly related with this issue - why are you even using Cygwin with Ruby and Firewatir? Just out of curiousity what's the real life usecase.

simple : i am coerced into using windows. but i do like the wealth of the gnu environment, for starters using bash instead of cmd is a real productivity gain.
besides the whole cygwin install/update model is just great.
So well it is just convenient to install and use ruby from the cygwin install instead of the ruby one click installer.

that was for the first point.

second point is i am evaluating watir and trying to figure out if it is really a benefit compared to selenium for instance (so far i am not convinced but willing to really investigate the issue). so i need to see the same testing script working on both ie and firefox. following andy comments on http://jira.openqa.org/browse/WTR-453 i have been able to get watir to work with IE too.

that was the second point

last but not last, i faced plain not-working-firewatir going through the route of the watir installation guide http://watir.com/installation/#win
so i opened up a discution on stackoverflow there: http://stackoverflow.com/questions/3602466/firefox-and-watir-wouldnt-work-on-windows-due-to-a-singularize-method-not-found/

that was the last point.

i think having watir actually support cygwin seems really easy honnestly (about 3 lines to update, only 10 caracters for firewatir), so it is worth doing i'd say.

You may be interested to know that I tested early versions of Watir on cygwin regularly. There is some code in our unit tests which is there specifically to support the file syntax of cygwin.

If this is still a problem, please report it here: https://github.com/watir/watir-classic/issues