title: Error while making SummarizedExperiment
body: <p>I want to make a SummarizedExperiment,
  I have  the count table in this format in FeatureCount.txt</p>
  
  <pre><code>         SRR1554537 SRR1554538  SRR1554541  SRR1554535  SRR1554536  SRR1554539
  1/2-SBSRNA4        39   66         72             23            16      7
  A1BG               221  113        226           146             36   126
  A1BG-AS1           393  296        527            276            39   258
  A1CF                 8  7          5                1             0    4
  A2LD1               97  208       171             181             72    110
  </code></pre>
  
  <p>I have the phenotype Data in this format:</p>
  
  <pre><code>              SampleName    RUN Age sex tissue  disease
  SRR1554537  R3452_DLPFC_polyA_RNAseq_total  SRR1554537  -0.384  female  DLPFC   control
  SRR1554538  R3462_DLPFC_polyA_RNAseq_total  SRR1554538  -0.4027 female  DLPFC   control
  SRR1554541  R3485_DLPFC_polyA_RNAseq_total  SRR1554541  -0.3836 male    DLPFC   control
  SRR1554535  R2869_DLPFC_polyA_RNAseq_total  SRR1554535  41.58   male    DLPFC   control
  SRR1554536  R3098_DLPFC_polyA_RNAseq_total  SRR1554536  44.17   female  DLPFC   control
  SRR1554539  R3467_DLPFC_polyA_RNAseq_total  SRR1554539  36.5    female  DLPFC   control
  </code></pre>
  
  <p>Here is my code:</p>
  
  <pre><code>count_feature &lt;- as.matrix(read.table("featureCount.txt", header = TRUE, stringsAsFactors = FALSE))
  phenoData &lt;- read.csv("Pheno_Data.csv", header = TRUE)
  col_data &lt;- DataFrame(phenoData)
  
  row_data &lt;- relist(GRanges(), vector("list", length= nrow(count_feature)))
  mcols(row_data) &lt;- rownames(count_feature)
  
  Brain_Es &lt;- SummarizedExperiment( assays = list(feature_Count= feature_Count), rowRanges = row_data, colData = col_data)
  </code></pre>
  
  <blockquote>
    <p>Error in <code>rownames&lt;-</code>(<code>*tmp*</code>, value = c("X", "SRR1554537", "SRR1554538",  : 
      invalid rownames length</p>
  </blockquote>
  
  <p>Can you explain the error?</p>