Closing paths

Hi all
Im a newbie here so please be gentle. I have a sainsmart 3018 cnc router/laser engraver ive managed to make a few engravings that turned out ok on. But… im not skilled with cad programs and certain images i try to engrave: mainly with “cut inside shape path” disappear from preview. I was told it may be because im not closing paths. I have no idea how to do that could anyone help. Ive attached the image of what im trying to engrave. Also a pic showing nothing in the preview window The image is there momentarily then dudappears.

The reason it does not show in the preview window could be the bit size is to big. Try putting in a vbit or maybe a 1/16" bit and see what you get.