US STOCKS-S&P 500 ends flat; Fed sees risks but unlikely to reverse course

* Fed not likely to reverse course on rates despite risks* Disney’s 3.8 pct drop weighs on Dow
* Indexes: Dow down 0.6 pct, S&P down 0.02 pct, Nasdaq (NasdaqGS: NDAQ – news) up0.4 pct (Updates close with Cisco up, Twitter (Swiss: TWTR.SW – news) down after the bell;latest volume)
By Caroline Valetkevitch
Feb 10 (Reuters) – The S&P 500 ended flat on Wednesday,losing gains late in the session as investors digested commentsby Federal Reserve Chair Janet Yellen, who k