Diff::LCS on Edge

Hi all,
  In one of my projects I'm using the Diff::LCS Gem (via "require
'diff/lcs'" in the appropriate model) to provide wikki-style diffing
between versions of text. It was working fine and dandy until I
upgraded the project to Edge Rails a couple days ago. Now, calls to
Diff::LCS::Hunk.new(..) throw undefined method errors. Calls to
Diff::LCS.diff work fine though, so I know that the require worked and
the library was found. I haven't played on The Edge much, so I'm not
sure if there's something special I need to do with regards to extra
libraries. Any helpful suggestions would be appreciated. Thanks.