Hi Gene,
Problem is .NET does not support COM dll's very well. You could create a RDC app in .NET but we did not support it. And CR 2008 does not ship the RDC but it does come with the Embedded Report Designer that is integrated into VS 2008 IDE. It was able to use DSR's but it's still going to have problems with the old ones.
Problem is when upgrading it doesn't know what to do with the DSR files either, I think.
So once again, they must have a working version of this application somewhere, export to RPT format from the viewer and then VS 2008 and CR for VS will be able to use the RPT's.
You can find sample for .NET here:
NET RAS SDK Samples - Business Intelligence (BusinessObjects) - SCN Wiki
Don