15-05-2014 11:57 - edited 15-05-2014 12:10
Because I faced the same issue today and although the Nokia Multimedia Converter was last updated in the year 2003, it did the trick for me. Instead of giving the setup.exe your Nokia Account, go back one step, and use this to ‘register’ that product.
In that converter, as audio, select AMR Wideband (WB AMR) which creates .awb files. Those have a sampling rate of 16 000 Hz which is great for HD-Voice like audio books. Actually for voice-only media, I went for a bit-rate of just 12.2 kbps, still great as explained by Wikipedia. With that bit-rate only go for standard AMR if your phone does not support the wideband variant, because there is not difference in size.