OK, I googled - you shold be able to do this simpler. Assuming you don;t have an index.html in your forum root, simply add the following line to your htaccess
RewriteRule ^(index\.html)?$ view.php?pg=xxxxx[QSA,L]
Then when someone visits
http://mysite.com your webserver will try and load up index.html which will be rewritten to view.php?pg=xxxxx (you swap xxxxx for the web template page identifier) and load up
http://mysite.com/view.php?pg=xxxxx someone requesting
http://mysite.com/index.php will still get that...