You may consider it to be beyond the scope of your abilities and are crippled by self-doubt or you have merely consistently put it off to another time, allowing the mundane demands of everyday life to take precedence. You must cast aside your self-doubt and steel yourself against the distractions and temptations that will test your resolve. Only by embracing the struggle ahead of you will your dreams be realized. A lone ant carrying something implies that there is something in your life which holding you back from attaining your goal; determine what it is, rid yourself of it and you will find yourself free to act.
A line of ants marching through your dream signifies a very different situation, that you lack a driving ambition. You meander through life listlessly without a purpose. The result is numbing repetition, each day a mirror of the preceding. Your mind rebels at this stagnation, urging you to find a purpose, something to strive for that will infuse your actions with meaning. The longer the line of ants the more stultifying you find your life.
A swarm of ants, internally chaotic but moving forward quickly, purposefully, unstoppably, suggests that you have begun you realize your ambition. You stride through the world with a goal in mind, success and satisfaction to follow. You know that there are challenges ahead but you have confidence in your ability to overcome them.
If you dream that you yourself are covered in ants it means that the barriers to success are being created by yourself. That you are inadvertently holding yourself back; it could be through lack of self-confidence or self-respect, self-destructive behavior or simply a lack of drive. Whatever it is it is in your power to stop.
The image of an object, or person, covered in ants is a hint. It could be a way of figuring out the next step, how to continue pursuing your goals. Alternatively it could be the clue you need to rid yourself of whatever influence is holding you back, the first step on the long journey of self-actualization. Or it could be the way to figure out your life, of determining what exactly you should be doing, how you should orient your life. The ants are there to make you sit up and pay attention, to direct your mind to a particular idea. Everything else is up to you.