In admin area, after upgrade, I've this error:

[Warning] file_get_contents(C:/xampp/htdocs/ss/cms/javascript/tinymce.template.js) [function.file-get-contents]: failed to open stream: No such file or directory
GET /ss/admin/newsletter/

Line 472 in C:\xampp\htdocs\ss\sapphire\core\Requirements.php
Source

463       
464    }
465    
466    /**
467     * Load the given javascript template with the page.
468     * @param file The template file to load.
469     * @param vars The array of variables to load. These variables are loaded via string search & replace.
470     */
471    function javascriptTemplate($file, $vars, $uniquenessID = null) {
472       $script = file_get_contents(Director::getAbsFile($file));
473       foreach($vars as $k => $v) {
474          $search[] = '$' . $k;
475          $replace[] = str_replace("\\'","'", Convert::raw2js($v));
476       }
477       $script = str_replace($search, $replace, $script);
478       $this->customScript($script, $uniquenessID);

I believe that the trunk version of the newlsetter module will work without that modification, but your fix should be okay for your need.

FYI: The tinymce.template.js file wasn't forgotten, it was intentionally removed.

Which version of the newsletter module are you using?

This error comes with the 'stable' version. The 'unstable' trunk version no longer has this problem - and should be stable enough for production, according to Sam in this post