I tried the Crystal Reports 2013 designer (30-day eval) - got the same error in Preview as within the Visual Studio designer ("Failed to load database information. Details: The database connector 'crdb_oracle.dll' could not be loaded. The correct version of the database client for this database type might not be installed.")
Again, this is a report .RPT originally created with CR10 using the native Oracle driver - now I'm running it from CR13 SP1 on a Windows 2012 (64-bit) server with Oracle 12c ODP insalled (64-bit version). I actually got data loaded at run-time in my ASP.NET application (created in Visual Studio 2013 compiled as 64-bit) running from this same server using this same report .RPT. Is there any way to get the data loaded into the .RPT in Preview from the CR designer?