Microsoft Knowledge Base Article 303431 contains the following summary:
The Microsoft Cluster service (MSCS) in Microsoft Windows Server 2003 and in Microsoft Windows 2000 Server cannot verify that clustered resources are able to run on all nodes in the cluster. For example, only one node can ever have a physical handle to a disk, and because of this, it is not possible to verify that another node can bring the disk online without disrupting the other node. It is the responsibility of the administrator to verify that the cluster is configured properly and that all groups can failover to the appropriate nodes.
See the "Test node Failure" topic in on-line Help in the Server Cluster section for ways to test if your server cluster will failover properly. This should be done before the server cluster is put into production to verify that it will provide a highly-available cluster solution. Some resources will go online on one node in the cluster but not on others for a variety of reasons. This article describes a few of the reasons why resources may come online on one node but not on any of the others.