将推文存储在RStudio中的MongoDB中

Question

我正在尝试将推文存储到RStudio中的MongoDB中。我收到以下错误。

> my_oauth<-OAuthFactory$new(consumerKey=consumerKey,consumerSecret=consumerSecret, requestURL=requestURL,accessURL=accessURL, authURL=authURL)
> my_oauth$handshake(cainfo = system.file("CurlSSL", "cacert.pem", package = "RCurl"))

* Hostname was NOT found in DNS cache
* Could not resolve proxy: host
* Closing connection 7
Error in function (type, msg, asError = TRUE)  : 
Could not resolve proxy: host

我的系统是Ubuntu 14.04。我该如何解决这个问题？