Step 6 solves only two of the last layer edges, the final two will be flipped in Step 7. just make sure you are performing the algorithm by holding the cube with an edge cubie in the correct location (although not necessarily flipped correctly) from the front perspective. otherwise, the edges will just cycle around. in our example, the green-white edge is in the correct location. most of the time one instance of the algorithm will do, but occasionally it does take a second run through. let me know if that helps!
Questions/Concerns? Private Message
me and I'll be glad to help!