Error code 6 - with Delta keyer / clean plate - win 10

Keep getting this error- ten the UI stops updating.
Simple 4k DNG seq with Green screen - add clean plate - add DK - then error....
tends to happen as soon as I put the DK into the viewer with 1 or 2...
Exact same function works perfect in Fusion 9 direct
thanks
Simple 4k DNG seq with Green screen - add clean plate - add DK - then error....
tends to happen as soon as I put the DK into the viewer with 1 or 2...
Exact same function works perfect in Fusion 9 direct
thanks