M.C.
My daughter did this at that same age--it lasted a couple of months and then disappeared on it's own. I also followed Healthy Sleep Habits, Happy Child, which did work eventually to produce a (now) great sleeper. Babies reorganize their sleep patterns frequently and that is what I think is happenening at this age. My daughter at 7 months slept as follows: nighttime 7:30pm-7am. Nap 8:30-9:15, 12:00-12:45, 3:30-4:15. At about 10 months, she totally changed things on us and slept at night from 6:30pm-5:00am with naps: 8-10:30am and 1:30-2:15pm. Then, around 14 months she got on her regular schedule (she is 2 now) and she sleeps from 8-6at night and naps from 12-2:30 during the day. Hope this helps. Just keep following the book and she'll get there. If she seems happy, she's fine. Don't make yourself crazy over it like i did--it seemed as though as soon as I stopped stressing over it, things fixed themselves. Good luck--I know how badly you want those long naps (believe me--I DO!)--I promise they WILL come!