Problem with twitteR package

Hey Guys,

I just started fooling around with the twitteR package in order to get a record of all tweets from a single public account. When I run userTimeline, I get the default 20 most recent tweets just fine. However, when I specify an arbitrary number of tweets (as described in the documentation from June 14th, 2011), I get the following warning:

bjaTweets<-userTimeline("BeijingAir", n=50)

Warning message:
In mapCurlOptNames(names(.els), asNames = TRUE) :
  Unrecognized CURL options: n

Does anyone familiar with the twitteR package know what is going on with options? Alternatively, if there are any other simple means for getting this sort of data?

Steve