An obstacle on your path acting like a barrier indicates that you are blocking your progress with regard to the subject matter of the dream. This is regardless of the fact that you did not put the obstacle there in the dream. If you know who put it there then you are letting the influence of that person block you from doing what you need to do. If it is non-personal, such as wet cement on the pavement, you need to improve the health of your colon in order to continue in the direction of your goal.
A barrier that acts like a fence means you suppress your feelings. This is used to mark your personal space. In dreams this is a symbol of sharing and indicates suppression of feelings. You do not share your feelings with others and more importantly you do not acknowledge your feelings yourself. Feelings come from your heart and persistent suppression can lead to health problems in this area. Also look for symbols to do with your head such as roofs or being up a height as these dreams are often asking you to move your centre of consciousness down from your head and into your heart.