To dream that you are walking on a tightrope, indicates that you are in a very precarious situation. You need to proceed carefully and weigh all the pros and cons of your decisions.
Walking a tightrope can mean:
You're feeling pressure to maintain a delicate balance or "walk a thin line" somehow in your life
You're feeling a risk of failure or embarrassment, represented by the risk of falling off of the dream tightrope