If you have the Flash2 plug-in (or later) and get a puzzle piece icon below using Netscape Navigator 2.0 or above then the Flash MIME has not been set correctly on the server yet.
MIME Type: application/x-shockwave-flash Suffix: .swf
This version has type="application/x-shockwave-flash" included
It may or may not display Flash without the MIME being set.