[galaxy-user] Trouble with RNAseq analysis

Hi everybody, I am trying to analyze the differential expression between two RNAseq samples. But I found many troubles aligning my reads. I will describe what I did. First I groomed the FastQ files (2). Then I uploaded the Sorghum genome and aligned the reads to it with Tophat. Aftter that, I tried to use Cufflink with the BAM file of Tophat, using as annotation file an uploaded GTF file and the Sorghum genome, but I received an error message in the three outputs of Cufflink. I tried to align against new brand Maize genome (now at Galaxy), and the same messages. I also converted the BAM file to SAM, but the same. Any advice? What was wrong? Thanks in advance. Cristian