Having a Problem Creating a Template for CloudWatch Metrics

I am trying to create a template to return a list of Application Load Balancers.

I am using the following query:
dimension_values(us-west-2,AWS/ApplicationELB,RequestCount,LoadBalancerName)

I did try running some of the sample queries on the CloudWatch datasources page successfully, but it seems like when I try to get dimension values it doesn’t work.

e.g. regions(), namespaces(), and dimension_keys(namespace) work.

This query doesn’t return any values for some reason. Below is a screen shot for context…

What am I doing wrong?

Thanks

Kurt