I registered via that site in last November. it was $15 USD as I recall. I don't see why he would refuse the money 
Let me know if you find a mpeg1 converter that works well with RiVA. I had to redo my computer and forgot which one i was using. I had tried several and the one I thought i was using no longer even produces mpeg1 files on my system, well, that's not 100% true, it does produce files but they are all distorted.
E.M. Total Video Converter - Version 3.71 (for Windows)
So, you went through the process and received a registered RiVA?