Problem with Adjoint Catchment Processing

[WillKellas]

Hi I am relatively new to ArcGIS.

I have installed ArcGIS 10 along with HEC-GeoHMS 10 (includes ArcHydro). I have delineated my catchments and dainage line but when i attempt to make aggregate catchments using the "adjoint catchment processing" function it gives the following error:

"shapefile is unable to be projected" and when i check the box nothing shows up.

Does anyone know why this is happening?

[WillKellas]

Sorry, the exact wording is:

The following data sources you added are missing spatial reference information. This data can be drawn in ArcMap, but cannot be projected"