It is very easy to display a flash/shockwave object in your page:
1) Attach the flash/shockwave file to your page.
2) Retrieve the URL of this attached file: right-click on the file, display its properties, and copy its URL.
3) Take the HTML code below, and replace the src embedded URL with yours.
4) In wiki editor mode, copy/paste this HTML code into your page, where you want to display/run this object.
<embed
src="http://placename.netcipia.net/xwiki/bin/download/spacename/pagename/file.swf"
type="application/x-shockwave-flash" width="XXX" height="YYY"></embed>
In the URL, you can also point to an external flash file located on any web site.
That's it :-)