On my computer BlacklightPoster.icc is located in the Common Files > Adobe > Color Profiles folder. You could try doing a search on your computer. If it is in a different folder, move it to the correct folder. If it is not on your computer at all, you may need to uninstall and reinstall Photoshop. If you are using Photoshop CC, I'd recommend doing the uninstall/reinstall using the Creative Cloud Cleaner tool.