If by "template" you mean a Dreamweaver Template file (.dwt) there are a couple reasons that might happen, the most common one is renaming the Templates folder that DW creates, or moving the .dwt file out of the Templates folder.
For DW to properly handle .dwt template files, they have to be in the folder that DW creates (Templates) which will reside in your local root folder.
In 5.5, I believe the option was File > New > Page From Template.