Unfortunately, this, like other teachings of Rebbi Nachman, is being quoted in error (he also never said "the whole world is a very narrow bridge...", but he did say "sometimes a man must cross a very narrow bridge"). the full text can be found here - http://www.breslov.com/international/likutei_mohoron/lt08.html (likutey moharan tinyana 34). Essentially he is speaking about the importance of being able to gain a perspective that incorporates the shoresh of simchadik event. I think the most telling omission is the lack of the word "tamid-constantly"

Is there a daf yomi yerushalmi shiur as well by any chance?