Problem making homemade bounty bars
From your comment:


  I dip the bars into melted chocolates and roll, using a fork.


If you want to coat something in chocolate, you typically need much more chocolate than you expect. The height of the chocolate should be high enough to submerge the praline or bar without rolling, otherwise you start to loose material - as you noticed. Simply dip, lift out (let excess chocolate drip off) and place on a rack or on parchment to harden. Do not put the bars in the refrigerator while the chocolate is still soft.

Another approach would be to emulate the industrial process of pouring the chocolate over the bars (on racks, parchment under the racks), but the same rule of preparing more chocolate than absolutely neccessary applies. Catch the drips and re-use, if possible.

Are you satisfied with the filling, or could you tweak it a bit to make it more stable? This might also be a way to make handling the bars easier. And if nothing helps, coat twice - once to somehow cover the bars and to contain all coconut crumbs (like a crumb coating in cake decorating), once to get a nice, even cover.