[galaxy-user] How to lauch bulit cluster on Cloudman?

Dear all, I just established Galaxy Cloudman on Amazon EC2. I created a cluster named "exon_capture" and uploaded a lot of data to it. After some analysis, I terminated the cluster. The second time I wanted to get access to the "exon_capture" cluster, I created a new instance under the "exon_capture". However, under this instance, the "access galaxy" button is in grey and not active. I tried several time, but the button was always in grey. Does anyone know what's wrong? Did I miss something? It may be a very simple question, but it bothers me a whole afternoon. Thanks a lot! Yan