It doesn't say your script is missing, it tells you that there is no program TexturePacker
in the /usr/local/bin
folder:
/usr/local/bin/TexturePacker: No such file or directory
You may on occasion have to delete the app from the device/simulator to force Xcode to transfer the entire app. Sometimes Xcode just doesn't catch up replacing all assets, though if I remember correctly this is mostly related to deleting files from the app.