VN I'm don't know how to Fix that problem plss and with apk needed to fix that eror script

[Akagami8103873]

I'm sorry, but an uncaught exception occurred.
While running game code:
  File "game/script/inventory2.rpy", line 27, in execute
  File "game/script/inventory2.rpy", line 27, in execute
  File "game/script/inventory2.rpy", line 48, in execute
  File "game/script/inventory2.rpy", line 132, in execute
  File "game/script/inventory2.rpy", line 202, in execute
  File "game/script/inventory2.rpy", line 202, in execute
  File "game/script/inventory2.rpy", line 203, in execute
  File "game/script/inventory2.rpy", line 205, in execute
  File "game/script/inventory2.rpy", line 209, in execute
  File "game/script/inventory2.rpy", line 231, in execute
  File "game/script/inventory2.rpy", line 235, in execute
  File "game/script/inventory2.rpy", line 240, in execute
  File "game/script/inventory2.rpy", line 249, in execute
  File "game/script/inventory2.rpy", line 251, in execute
NameError: Name '4000 / 4000' is not defined.