Asymmetric argument in R

Question

When using the package twitteRfor R, I get the following error

Error in strsplit(response, "&") : non-character argument twitter

when trying to send my oauth credentials using this code

cred <- OAuthFactory$new(consumerKey=consumerKey, consumerSecret=consumerSecret,
                         requestURL=reqURL, accessURL=accessURL, authURL=authURL)

cred$handshake(cainfo=system.file("CurlSSL", "cacert.pem", package="RCurl"))

If I use httpinstead https, I get an error

Error: Forbidden

I work on a windows machine.