Changing forum software, trying to redirect old to new with mod_rewrite

[al2six]

I'm changing the forum software I'm using and i have imported all the posts from the old forum into the new. What I'm trying to do is redirect users who are trying to view a post on the old software to the same post on the new software. here's what i put in my .htaccess file:

RewriteRule ^forum/index.php?showtopic=(.*)$ forumredirect.php?topic=$1 [L]

and then forumredirect.php takes the topic id # and uses a 301 to send the user to the new url. however, this isn't working. when i attempt to view a post on the old software, it loads just fine, instead of sending me to forumredirect.php

anyone know what i'm doing wrong?

thanks

[JamieJelly]

I'm no mod_rewrite expert but don't you need to turn the mod_rewrite engine on?

e.g

RewriteEngine on
RewriteRule ^forum/index.php?showtopic=(.*)$ forumredirect.php?topic=$1 [L]