Warning message and URLs not found on menu items
The warning looks like a PHP incompatibility. So either fix the code that's been triggering it (and at best provide a patch for it on drupal.org) or change MAMP's PHP version. Probably to something lower as it is now.

The URL not found error looks like as if you misconfigured your .htaccess file. Ensure this file exists and maybe uncomment the following line.

RewriteBase /