Ah yes, the problem is that XMPlay is erroneously sending the hashtag to the server, and the request is failing with a "Bad Request" status as a result. Here's an update that leaves out the hashtag:
www.un4seen.com/stuff/xmplay.exeLet me know if you still have any trouble with it. Btw, you probably don't need to include the entire filename in the hashtag, the extension alone should suffice to show XMPlay that it's a supported filetype. Another option is to set an "Open from clipboard" or "List - Add from clipboard" keyboard shortcut (possibly global) and press that after copying the URL to the clipboard. This method doesn't check the extension, so shouldn't require any hashtag fiddling.