I'm typing this from phone so keeping it short but that error usually means the band-in-a-box instruments folder under your sampletank instruments folder is not there or in wrong sub folder. When you installed 2015 it reinstalled hi-q set 1 unless you unchecked that box during installation . So that might have "upset" your sampletank instruments folders tree


Win10Pro,i9,64GB,2TBSSD+20TBHDDs,1080TI,BIAB'24,Scarlett18i8,Montage7,Fusion 8HD,QS8,Integra7,XV5080,QSR,SC-8850,SPLAT,FL21&others,Komp.14,IK suite&others, just a guitar player-AXE FX III &FM9T, FishmanTP, MIDIGuitar2, GK2/3'sw/GI20