To make the Delfina card work, you need at least the hardware driver (the file is "delfina.library") and an application that can use it.
The latest "official beta" version of the library can be found at the
Individual Computers site (look for it in the Support section).
For a long time there have been problems with the "official" libs and the Delfina MPEG audio players (the "freeze bug"). If these are still there with the latest library version, then I can send you an older, patched lib (inofficial hack) that seems to work better.
Just send me an e-mail: smack42 (at) web (dot) de
Although it has been mentioned before: you can find some Delfina applications on Aminet, simply search for "delfina".