Help me redirect forum links to new domain

[mp4sverige]

I have moved my forum to new domain and cant find a good way to redirect all links.
i have tried several rewrite rules in .htaccess but nothnig works.

the old forum was phpbb and i have now migrated to vb so all links are different.

exemple of old link:
http://www.old-domain.com/forum/view...php?t=737&f=16

i would like to redirect all old links to the main page on new domain:
www.new-domain.com/forum.php

i have tested the following code, but it only displays an blank page with text "Page not found"

RewriteEngine On
RewriteCond %{REQUEST_URI} forum
RewriteRule ^(.*)$ http://new-domain.com/forum.php$1 [R,L]