Hi Cathy...just some general info for you regarding your Kolach...
If you leave about a 2" 'border' around the filling; before you roll it up; this usually will eliminate the filling spilling out the ends/sides.
When rolling up, try to roll 'less tight'; as the dough expands, during the baking process and can squeeze the filling out and also split the dough.
You don't need to submit the dough recipe; but what basic ingredients are you using? Sometimes if the dough (itself) recipe is too 'rich' in butter that (also) can cause some splitting. I can submit some recipes (after supper) and see if one appeals to you. Love those nut rolls too!