is the power nailer not penetrating the concrete? i framed my entire basement using steel cut concrete nails and a 3lb. hammer. if you don't want to do this, i would just use a high quality construction adhesive assuming you are not construction load bearing walls. just construct the sill plate and studs on the floor, measuring each stud separately because the floor probably isn't perfectly level, and raise it into place and add the top plate, unless you are nailing the studs to floor joists above. if you want to use anchors, get a good masonry drill bit and follow the instructions that come with the anchors for sizes, etc. hope that helps.