title: Function write.csv returns an error
body: <p>The R function <code>write.csv</code> returns an error.</p>
  
  <p>Here's the data.frame I want to write:</p>
  
  <pre><code>&gt; VaRStats
                 A Index    B Index      C Index
  Daily VaR     -0.65006    -0.50391     -0.5557
  Daily CVaR    -0.75679    -0.57491    -0.65174
  5 Days VaR     -1.4204     -1.0077     -1.2269
  </code></pre>
  
  <p>Here's the class of <code>VaRStats</code>:</p>
  
  <pre><code>&gt; class(VaRStats)
  [1] "data.frame"
  </code></pre>
  
  <p>And here's the <code>dput()</code> output of <code>VaRStats</code>:</p>
  
  <pre><code>&gt; dput(VaRStats)
  structure(list(`JWFXA Index` = structure(list(`NA` = -0.650061101980277, 
      `NA` = -0.756791819719978, `JWFXA Index` = -1.42035638029947), .Names = c(NA, 
  NA, "JWFXA Index")), `CCYT1 Index` = structure(list(`NA` = -0.503912574910245, 
      `NA` = -0.574907003405759, `CCYT1 Index` = -1.00773735259718), .Names = c(NA, 
  NA, "CCYT1 Index")), `FX Multistrategy Index` = structure(list(
      `NA` = -0.555699685451229, `NA` = -0.651738541799373, `FX Multistrategy Index` = -1.22688572580144), .Names = c(NA, 
  NA, "FX Multistrategy Index"))), .Names = c("JWFXA Index", "CCYT1 Index", 
  "FX Multistrategy Index"), row.names = c("Daily VaR", "Daily CVaR", 
  "5 Days VaR"), class = "data.frame")
  </code></pre>
  
  <p>The error generated though the <code>write.csv</code> function</p>
  
  <pre><code>&gt; write.csv(VaRStats, "SummaryStats.csv")
  Error in write.table(x, file, nrow(x), p, rnames, sep, eol, na, dec, as.integer(quote),  : 
    type 'list' not implemented in 'EncodeElement'
  </code></pre>
  
  <p>How is that possible?</p>