Hi,
I’m not using the twircurl but you can check the OAuth key (oauth_token) value format it should be USER_ID-KEY like 693025-ioh5o2i352h3o52hklk3jh34jh5
The sample above is the correct access token to make the application able to post update or else, i suspect the key that you get when entering wrong PIN code is value request_token which actually use same name (oauth_token)