Game suddenly won't start after selecting my file

And this error pops up:

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Pokemon Uranium
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Exception: RuntimeError

Message: Script error within event 18, map 59 (Route 03):

Exception: NoMethodError

Message: Section023:8:in `spriteset'undefined method `values' for nil:NilClass

***Full script:

pbTrainerIntro(:BLACKBELT)
Kernel.pbNoticePlayer(get_character(0))
pbCallBub(2)


Interpreter:243:in `pbExecuteScript'

* PokemonUtilities:1032:in `pbExclaim'

* PokemonUtilities:1043:in `pbNoticePlayer'

(eval):2:in `pbExecuteScript'

Interpreter:1600:in `eval'

Interpreter:243:in `pbExecuteScript'

Interpreter:1600:in `command_355'

Interpreter:494:in `execute_command'

Interpreter:193:in `update'

Interpreter:106:in `loop'



Interpreter:276:in `pbExecuteScript'

Interpreter:1600:in `command_355'

Interpreter:494:in `execute_command'

Interpreter:193:in `update'

Interpreter:106:in `loop'

Interpreter:198:in `update'

* Scene_Map:103:in `update'

* Scene_Map:101:in `loop'

* Scene_Map:139:in `update'

* Scene_Map:68:in `main'



This exception was logged in

C:\Users\becca\Saved Games/Pokemon Uranium/errorlog.txt.

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OK
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I think it might have to do with me saving in front of someone before he decides to battle me, but I have no idea how to fix this