title: Error and warning messages with qplot
body: <p>I have a data set <code>intrK1</code> which is having some observations and 3 variables that is <code>V1</code>, <code>V2</code>, <code>V3</code>. This is my command:</p>
  
  <pre><code>qplot(log10(intrK1$V1),intrK1$V3,geom="point",fill=-intrK1$V3,xlab="Addtag(@)",ylab="Count")+geom_point(aes(weights=-intrK1$V2), position="dodge")
  </code></pre>
  
  <p>It is showing an error which I am unable to figure out.</p>
  
  <pre><code>Error: missing value where TRUE/FALSE needed
  </code></pre>
  
  <p>In addition: Warning messages:</p>
  
  <pre><code>1: In Ops.factor(intrK1$V2) : - not meaningful for factors
  2: In Ops.factor(intrK1$V2) : - not meaningful for factors
  </code></pre>