Can't Deploy Configuration

After following this KB article, I can't deploy configurations anymore. Here's the error message I'm getting:

   at LabManager.Backend.CDeployableVMContainer.DeployVMs(DeployOptions options, CVirtualMachine[] vms) 
   at LabManager.Backend.CDeployableVMContainer.Deploy(DeployOptions deployOptions, List`1 vmList)

My Hosts, Datastores and Resource Pools all appear to be online and OK. vCenter seems to be working normally.

Any ideas about how to resolve?

Thanks!