title: Error in `V<-`(`*tmp*`, value = `*vtmp*`) : invalid indexing
body: <p>I used the bibliometrix function in R, and want to plot some useful graphs.</p>
  
  <pre><code>library(bibliometrix)
  ??bibliometrix
  D&lt;-readFiles("E:\\RE\\savedrecs.txt")
  
  M &lt;- convert2df(D,dbsource = "isi", format= "plaintext")
  results &lt;- biblioAnalysis(M ,sep = ";" )
  S&lt;- summary(object=results,k=10, pause=FALSE)
  plot(x=results,k=10,pause=FALSE)
  options(width=100)
  S &lt;- summary(object = results, k = 10, pause = FALSE)
  NetMatrix &lt;- biblioNetwork(M1, analysis = "co-occurrences", network = "author_keywords", sep = ";")
  
  S &lt;- normalizeSimilarity(NetMatrix, type = "association")
  net &lt;- networkPlot(S, n = 200, Title = "co-occurrence network",type="fruchterman", labelsize = 0.7, halo = FALSE, cluster = "walktrap",remove.isolates=FALSE, remove.multiple=FALSE, noloops=TRUE, weighted=TRUE)
  
  res &lt;- thematicMap(net, NetMatrix, S)
  plot(res$map)
  </code></pre>
  
  <p>But in the  <code>net &lt;- networkPlot(S, n = 200, Title = "co-occurrence network",type="fruchterman", labelsize = 0.7, halo = FALSE, cluster = "walktrap",remove.isolates=FALSE, remove.multiple=FALSE, noloops=TRUE, weighted=TRUE)</code>, it shows error </p>
  
  <blockquote>
    <p>Error in <code>V&lt;-</code>(<code>*tmp*</code>, value = <code>*vtmp*</code>) : invalid indexing</p>
  </blockquote>
  
  <p>. Also I cannot do the CR, it always shows unlistCR. I cannot use the NetMatrix function neither.
  Some help me plsssssssss</p>