I see templates in Admin, but cannot change them

Hello, I have just upgraded a site from 1.38a to 1.51 (traditional manner) and installed a new template. I cannot change any template in Admin, not even to the Green one. (The site originally had a custom template, it will not change with the edit function in admin.) I know I have installed the new template correctly because I installed a fresh 1.51 in another directory and the new template into it, it works perfectly, and then compared the folder tree structure, its all the same. Something happened in the upgrade that will not allow me to save the edit I make to change the template. Any ideas? Thanks!!!! so much (I love the database /upgrade so I do not have to recreate the store)

For clarity, in your admin, you select tools -> template selection.
Here you see the templates installed and can preview Classic Contemporary Green and your custom template, yes?

Yes, I can see all three templates, The Custom Original Template, Green, my New Template, I choose Edit, select the template and it does not change.

In the past I have had server timeout issues when uploading files... perhaps the new_template files need to be uploaded to the server...
It sounds like you can access your includes/templates/YOUR_NEW_TEMPLATE/template_info.php files.