We just pushed a few minor tweaks to the templating system.
You can now preview any template by clicking the Preview (eye) icon next to the template that you want to preview. This will show you what your Switchboard would look like with the chosen template.
Also when you save a new or existing template, the system will now check for any errors and display them to you. It will also give you the line number where the error occurred, along with a brief description of that error.
Hopefully these few small changes will assist you in designing and using templates, and prevent your Switchboard from blanking out on you.
Please play and let me know if you have any queries.