1-If you have previous versions installed, browse to your /Addon folder and delete the following folders (if you don't have a particular folder, don't worry about it): AT4, AT5, AT6, AT7, BS1, BS2, CO1, CO2, CST, GO1, GRN, HAR, KM1, MHA, MTH, RAT, RAX, RH1, RNV, S04 through S15, TA1, YV2. ***DO NOT SKIP THIS STEP, IT IS REQUIRED!
2-Run bf1pack_v175beta.exe, and browse to your /Star Wars Battlefront II/Gamedata directory, then extract.
3-If you follow the first two steps EXACTLY the pack will be installed perfectly. At this point fire the game up and have fun!