Lucky bamboo leaves with brown tips are usually the result of fluoride burn or lack of humidity.
In many city water systems they add fluoride to the water, as a result this water can sometimes cause a fluoride burn in sensitive plants. If you suspect fluoride burn immediately change the water with distilled water or rain water. You can then cut the brown tips off. Be sure to cut the tips at an angle instead of straight across. If you think lack of humidity is the cause try misting the leaves every day or every couple of days.