I did find an archived version of the Yamaha site at
http://web.archive.org/web/20030602032352/www.yamaha.co.uk/xg/html/midplug/m_mid8.htm I don't know if the update is available there but have a look around and see. I know the trial versions for XP and 95 are there.
[This message has been edited by Nigel (edited 06-02-2005).]