You may add a new attribute loop="true" inside the param tag. If it is not specified, it is usually default to look="true".

e.g.

<object width="450" height="120"><param name="movie" value="http://mymedia.yam.com/*/2849003"></param><param name="quality" value="high"></param><param name="wmode" value="transparent" loop="true"></param><embed src="http://mymedia.yam.com/*/2849003" quality="high" type="application/x-shockwave-flash" wmode="transparent" width="450" height="120"></embed></object>