FYI there is a 'console' plugin you can get to help with what is causing the error
Here is the console, if anyone is interested to take a look:
TypeError: Cannot read property 'height' of undefined
at Sprite_Enemy.updateFrame (file:///C:/Users/Janey/Documents/hendryworkshop/monsterplanet/js/rpg_sprites.js:981:34)
at Sprite_Enemy.Sprite_Battler.updateMain (file:///C:/Users/Janey/Documents/hendryworkshop/monsterplanet/js/rpg_sprites.js:512:14)
at Sprite_Enemy.Sprite_Battler.update (file:///C:/Users/Janey/Documents/hendryworkshop/monsterplanet/js/rpg_sprites.js:493:14)
at Sprite_Enemy.update (file:///C:/Users/Janey/Documents/hendryworkshop/monsterplanet/js/rpg_sprites.js:952:37)
at file:///C:/Users/Janey/Documents/hendryworkshop/monsterplanet/js/rpg_core.js:3569:19
at Array.forEach (native)
at Sprite.update (file:///C:/Users/Janey/Documents/hendryworkshop/monsterplanet/js/rpg_core.js:3567:19)
at file:///C:/Users/Janey/Documents/hendryworkshop/monsterplanet/js/rpg_core.js:3569:19
at Array.forEach (native)
at Sprite.update (file:///C:/Users/Janey/Documents/hendryworkshop/monsterplanet/js/rpg_core.js:3567:19)