Dishwashers do not "roll". but they normally can be pulled out. Normal installation has the dishwasher slipped into a cabintet space exactly 24" widef from edge to edge, about 32+ inches from underside of top, to floor. Remember that there are two hold-down brackets either on the top of the DW, or sometimes on the upper sides, if countertop is granite. These keep it from tipping, and come off with one screw.
Here are some things that can be "mis-planned"
If any'extra' trims were added at the sides, that is a problem/
If the countertop is too low, the overhang or bullnose can interfere with the door.
If the DW is installed on rough floor, then thick floor tiles are installed, this can make it impossible to get out.
Please post some photos.