Recreated this tonight, steps used were:
Open XL4
Create new model for matrix, save
go to sequencer tab
Create new 40fps animated sequence
add model to sequence
create single timing mark around 10 seconds
add affect
drop the dots (searchlight) effect over the top as replace
go to effect property and try and change number of dots
immediate crash
Windows 8.1 update2 with all current patches
Attached is tonights debug plus two others relating to similar cause.