I wanted to use the ruby geocoder library on the windows machine, but the installation of the gem failed due to some weird error. I checked the rubyforge project page to see if someone else had a similar problems and someone actually had, but the bug was open for a long time. I decided to fix this issue and found that the problem was due to the fact that windows platform does not allow characters '?' and '&' in the filename with any escaping, period. The said files were used (in a very innovative way I must say!) to test the library by modifying http.rb to return the test datafile contents instead of fetching the URL from the net. (yay open classes in ruby!). The way I fixed the problem was to change the filenames to use '_' instead of '?' and '__' instead of '&'.
I wrote to the developer, but there was no response. Anyway I managed to create a new GEM with the changed files so that this should be installable on windows now. Here are the files if you want to try installing the gem. (Also including the tgz because... it got generated anyway!)