[galaxy-dev] Persistent jobs in cluster queue even after canceling job in galaxy

Hi All, I've been able to submit jobs to the cluster through galaxy, it works great. But when the job is in queue to run (it is gray in the galaxy history pane) and I cancel the job, it still remains in queue on the cluster. Why does this happen? How can I delete the jobs in queue as well? I tried qdel <job_id> as galaxy user but it says I am not authenticated to delete the job. Any help would be greatly appreciated. Thanks Ravi.