Getting Domains From Workflow Management Server

I am trying to get a list of domains from the Workflow Management server.  When I execute the code below:

 using (WindowsImpersonationContext impersonationContext = (User.Identity as WindowsIdentity).Impersonate())
            {

                SourceCode.Hosting.Client.BaseAPI.SCConnectionStringBuilder builder =
                new SourceCode.Hosting.Client.BaseAPI.SCConnectionStringBuilder();

                builder.Authenticate = true;
                builder.Host = "localhost";
                builder.Port = 5555;
                builder.Integrated = true;
                builder.IsPrimaryLogin = true;

                SourceCode.Workflow.Management.WorkflowManagementServer workflowManagementServer = new SourceCode.Workflow.Management.WorkflowManagementServer();
                workflowManagementServer.CreateConnection();
                workflowManagementServer.Open(builder.ToString());
                Domains d = workflowManagementServer.GetDomains();
                impersonationContext.Undo();

            }

I get the following error message:

Could not find stored procedure 'Server.mGetDomains'

Has anyone run into this issue before?