Hi,
typically to find the issue here:
search ( using the search field, not manually) for "PlayerPrefsxGetValue", you will probably find that you have two scripts, and so one is a duplicate, you only need one ( probably because Unity renamed it "PlayerPrefsxGetValue 1", or else because you pasted it manually but in a different location.
else, let me know. we'll debug further.
Bye,
Jean