You are correct: the three lines in question move the character from ROM to RAM, then redefine a total of 16 + 7 characters. There's a line somewhere that includes "POKE 756,40"; if you remove that as well, then I suspect the program will run but not have the redefined graphics.
There's a version at Atarimania: https://www.atarimania.com/game-atari-400-800-xl-xe-wild-strawberries_16753.html
Question: Which DOS are you running? On an emulated 400, with 16K of RAM, once you've got a DOS loaded there's not a heck of a lot of RAM available; I suspect the program is clobbering itself.