Replace Media stopped working

Hello,

My replace media plugin is not working anymore. When I replace Media, select my pdf file to “Just replace the file”, then click “Upload”, the screen goes to blank. Here is url I get:
http://www.jacksonprop.com/wp-admin/upload.php?page=enable-media-replace%2Fenable-media-replace.php&noheader=true&action=media_replace_upload&attachment_id=2344&_wpnonce=9c2287bb63

If I hit reload it brings up “Page not found” or “500: Internal Error”.

I’ve hired a programmer and contacted my web provider and they both were not able to fix. They said to contact plugin. So, I am contacting you in hopes that you can help me.

Thank you,
MonaE

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