Just thought I'd post this in case anyone else has issues trying to use the De0Nano control panel application. The problem I found is that the app is 32-bit only, and therefore requires 32-bit DLLs (which it neglects to include). The latest (V14 at time of writing) versions of Quartus are 64-bit only however. To resolve, install Quartus V13 or earlier, and add the path to the 32-bit binaries to your system PATH variable (e.g. c:\altera\13.0\quartus\bin) (NOT bin64).