title: R: error in qplot from ggplot2: argument "env" is missing, with no default
body: <p>I am using qplot from ggplot2 to plot the distances of seeds dispersed by different species in R. When I use <code>geom='density'</code>, it works just fine! But what I really want is a frequency/area plot, for which I get an error I do not know how to address.</p>
  
  <p>This works:</p>
  
  <pre><code>qplot(Dist,data=testx,geom="density",fill=Animal,log=c('x','y'),alpha=I(0.5))
  </code></pre>
  
  <p>This doesn't work:</p>
  
  <pre><code>qplot(Dist,data=testx,geom="area",fill=Animal,log=c('x','y'))
  
  Error in exists(name, envir = env, mode = mode) : 
    argument "env" is missing, with no default
  </code></pre>
  
  <p>Help? Thanks!</p>