If the File Browser keeps loading forever or Editor Plugin returns “Internal Server Error”, its most likely a file permission issue. Some servers with suPHP are configured so that PHP files that are writable (CHMOD 777) cannot be accessed, giving a 500 Internal Server Error.
To fix this, folder permissions must be set to 0755 and scripts to be 0644 (source)
Run these FTP commands in your wordpress root directory to set the correct permissions:
cd wp-content/plugins chmod 755 wp-filebase-pro cd wp-filebase-pro chmod 644 editor_plugin.php chmod 644 sync.php chmod 644 wpfb-ajax.php chmod 644 wpfb-async-upload.php chmod 644 wpfb-postbrowser.php chmod 644 wp-filebase_css.php chmod 644 wp-filebase_thumb.php
If this does not work and you still get an Internal Server Error, try 744 instead of 644 for script files.
If the File Browser is still not working, make sure your site URL in WordPress settings is set correctly (with our without the www.)