Both frozen juice concentrate and creme fraiche are not available in the place I live. Can I substitute these two indredients with something else?

Here's a way to make creme fraiche at home
http://www.epicurious.com/recipes/food/reviews/creme-fraiche-106036

Another possibility to replace the frozen juice concentrate is to use a shelf-stable juice concentrate - depending on your preference or what you think best goes with the carrot - like Ribena (blackcurrant) or Pomegranate Syrup (also called Pomegrante Molasses, but has no molasses in it).

The concentrate can really be substituted for any flavorful liquid such as regular juice, they're slightly different in sugar concentrations so you can either just add it in and wind up with a slightly different texture, or concentrate it yourself by reducing it by at least half, and cooling it. The crème fraîche can be switched out for either yogurt or sour cream. Crème fraîche tends to be more fluid than many sour cream varieties, closer to yogurt in consistency, so if you use a thick sour cream, just thin it out with either some milk or a bit of water.