Thread:Extension talk:PDFEmbed/parser error/reply

I've put in a pull request in the git repository for this extension that should fix your issue. Sounds like you're using a PHP version that doesn't support square bracket arrays, which is a new feature in PHP 5.4 and newer versions. If you don't want to wait for the pull request to be merged, you can go ahead and copy the change I made to your MediaWiki installation. :)

Hopefully that works!