I wanted to post this in case anyone else ever runs into this problem as I couldn't seem to find this solution anywhere else. I have a Server 2008 R2 cluster with 2 nodes. When I launched Failover Cluster Manager, it wouldn't show any cluster. When I tried to "Manage Cluster" and add the cluster name, it said I didn't have admin permissions to the node so I couldn't manage that cluster. Looking through the services, I noticed that the "Server" service (LanmanServer) was not running. I started the service and was able to access the cluster in Failover Cluster Manager.
If you lauch Failover Cluster Manager and it doesn't show any cluster:1. Check the "Server" service (LanmanServer) on each node and start it if it is not running.
2. Close Failover Cluster Manager and re-launch it.