* Nikkei stalls at 61.8 pct retracement of last year's fall * Market wary of profit-taking after big February rally * Profit-taking hurts recent gainers such as carmakers * Further earning improvements may be needed to extend gains * Daiichi Sankyo up on GSK tie-up By Hideyuki Sano TOKYO, March 2 (Reuters) - Japan's Nikkei share average rose on Friday following Wall Street's climb, but it struggled to break above key chart points and gave up some early gains on profit-t