Kontakt freezes Cubase

Hi,
I play a few notes on a Kontakt track, Cubase freezes. Midi still seems to work, but audio / all sound fails. I thought it might be a lack of memory issue, but it still happens with my VST performance at 10 %.
I have updated all software, including a full re-install of Komplete 8 (4 hrs)!
My Vienna Ensemble is fine, as are Stylus and Omnisphere. What is the issue with Kontakt?
Any suggestions?
Cheers,
Neil

It seems that the issue only applies to:

  • all African drum samples imported from an old Akai CD (the first four tracks in my Kontakt template)
    Is there some explanation why some Akai CDs don’t convert properly?
    Cheers,
    Neil