Routes in Ruby on Rails are case sensitive. It seems someone brought this up before, and it has been labeled will not fix.
http://rails.lighthouseapp.com/projects/89
Routes in Rails are case sensitive because URLs are case sensitive. From the W3C:
URLs in general are case-sensitive (with the exception of machine names). There may be URLs, or parts of URLs, where case doesn't matter, but identifying these may not be easy. Users should always consider that URLs are case-sensitive.