The code requires at least PHP 5.3. Dreamweaver does not support that PHP version, so it reports unknown, newer syntax as errors.
WordPress requires just version 5.2.4, but it recommends at least 5.4. My suggestion is to use always the latest stable version on the server, currently PHP 5.6. Your development setup should use exactly the same version as the server to avoid portability problems.
Upload a file with just <?php echo PHP_VERSION; ?> in it and look at it in a browser to see the version.
Then you have to find a better editor. You have multiple options:
- Switch to the new subscription based version of Dreamweaver.
- PHPStorm. Most professional developers use that nowadays. It is not free, but it comes with many features, including WordPress support and the option to select a project specific PHP version.
- Use another IDE like Eclipse or Netbeans.
- Use an Editor like Sublime or Notepad++. Both need a bunch of plugins to make your work comfortable.
If you have problems on the server, enable the debug mode, and install Query Monitor. This will tell you what the error says and where it comes from.