Both portaudio.dll  and  portaudio_x86.dll  seemed to do the trick. 

Many thanks. 

> The only thing I can think of is having both portaudio.dll ANd
> portaudio_x86.dll. Possibly rtpa.dll is linked with one, and some other DLL
> with the other. This will be fixed in the next upload.
>
> Regards,
> Mike