Extension:TemplateData has a wonderful feature: if you add a parameter to your template, the "Manage TemplateData" GUI editor automatically notices and asks if you want to import it.
Add 1 suggested parameter
If you say yes, however, the GUI displays a long response that sounds like a problem occurred:
Some parameters were not imported, because they already exist in the editor: name, address, zipcode, color, issmall, message
I suggest you get rid of the above message. All you need is the second line, informing the user that the new parameters were imported.
1 new parameter was imported: age