To Richard Hallas:
You write "RISCOS Ltd tested the DVD with the two systems mentioned and assured me that it works fine". Well, I'm a bit surprised that ROL didn't try it on an IYONIX pc; since they state that they are committed to offer Select32 for the IYONIX pc in near future I assume that they have an IYONIX pc and it shouldn't be that difficult to (temporarily) put one of their DVD drives into that one to check if the new DVD they offer works with it... but perhaps I'm wrong with my assumptions alltogether.
To hubersn:
Yes, the "CDBurn CD Reader" would be a good idea assuming it can read DVDs too