Help!

I keep getting the following error upon inserting a gallery:

Warning: DOMDocument::load() [domdocument.load]: I/O warning : failed to load external entity "/data/25/2/161/9/2487172/user/2723719/htdocs/WordPress/wp-content/uploads/20.xml" in /data/25/2/161/9/2487172/user/2723719/htdocs/WordPress/wp-content/plugins/wp-simpleviewer/wp-simpleviewer.php on line 783

Fatal error: Call to a member function appendChild() on a non-object in /data/25/2/161/9/2487172/user/2723719/htdocs/WordPress/wp-content/plugins/wp-simpleviewer/wp-simpleviewer.php on line 818

on this page:
http://www.brooksann.com/wp-admin/post.php

I've used this plugin before with no problems. I've also deactivated, deleted, and reinstalled.

Thanks in advance for your time.
L