Thread:Extension talk:PageAttachment/Fatal Error: Class ListFiles not found

I installed the PageAttachment extension on Mediawiki 1.17.0. I can see the File Attachment Box at the bottom of the page (with no attachments), but when I click the browse button I get the following error:

"Fatal error: Class '\PageAttachment\BrowseSearch\ListFiles' not found in .../wiki/includes/SpecialPage.php on line 404"

I get a similar error if I click the attachment button. Any thoughts?

Thanks, E