you could try the adaptec website for the aspi drivers i thinks thats where i got mine

if you want to mail me a couple of the the files you are trying to convert i will try them on my copy of disky.

it may have an issue with a4k and above cause its was written years ago and never finished properly cause the company that bought it went bust.

theres another proggie called bzone thats for the a series too http://www.bzone.be/ it supports all the yamaha samplers you could give that a try too