It looks like you need to have these files in that VST Sound folder:
FCP_SMT_001_Cubase.vstsound
FCP_SMT_002_Cubase.vstsound
FCP_SMT_004_Cubase.vstsound
FCP_SMT_005_Cubase.vstsound
FCP_SMT_008_Cubase.vstsound
FCP_SMT_009_Cubase.vstsound
at least that’s how’s it’s set up Cubase 8, 8.5, and 9. Since you’ve been able to locate them, I guess you should try moving them back.
As I recall, to place a sound sample onto a pad, you need to drag it from somewhere. So start mouse drag on the clip and end on the pad.