Hello everyone

I am working on RNA-Seq data analysis. when i running the following command in cuffmerge

$ cuffmerge -o 816840 -g '/home/iman/Downloads/yeast/genome/Saccharo.gtf' '/home/iman/Downloads/yeast/transcript.txt'

I encounter this error:

Traceback (most recent call last):
  File "/usr/bin/cuffmerge", line 580, in <module>
    sys.exit(main())
  File "/usr/bin/cuffmerge", line 526, in main
    run_log = open(logging_dir + "run.log", "w", 0)
ValueError: can't have unbuffered text I/O

Can anyone help me?