Help missing from Hydraflow Hydrographs

Today, one my clients was trying to look up some information for Hydrographs in the help content, but there was a problem, nothing happened.  Typically when selecting content from this program or any of the various Autodesk products, the user's guide pops up with content, index, and search options for the specific software.

After spending some time searching for a solution, I simply went back to an older version, in this case Civil 3D 2012, copied the following file, and overwrote the same one in Civil 3D 2013.

C:\ProgramFiles\Autodesk\AutoCAD Civil 3D 2012\HHApps\Hydrographs.chm

The hep content now works as expected.  The file in 2013 must be corrupt.  If you do not have access to a previous version of the software, please let me know and I would be happy to send the file.