SEO issue

[Gaming Perfection]

Hi,

I'm having an issue with getting the correct paths for when I enable the SEO option "Create URL's according to SEO link consensus (i.e. '/en/address')". I don't have vBSEO installed and am running vB Suite, with my home page being site.com and my forum at site.com/forum.

With the "Forum directory" option left blank the following occurs;
On site.com, successful translation to site.com/lang but when trying to go to the forum it goes to site.com/lang/forum.php, which returns a 404 error.
On site.com/forum, successful translation to site.com/forum/lang but the translation is lost when returning to site.com.

With the "Forum directory" set to /forum the following occurs;
On site.com, translation tries to go to site.com/forum/lang, which returns a 404 error.
On site.com/forum, translation goes to site.com/forum/lang/forum.php, which returns a 404 error.

In the default vB settings of "Site Name / URL / Contact Details", my forum URL is set to site.com/forum and my homepage to site.com

My .htaccess file is;

##Translation Mod Stuff##

RewriteEngine On

RewriteRule ^/?(af|sq|ar|be|bg|ca|zh-CN|hr|cs|da|nl|en|et|tl|fi|fr|gl|de|el|iw|hi|hu|is|id|ga|it|ja|ko|lv|lt|mk|ms|mt|no|fa|pl|pt|ro|ru|sr|sk|sl|es|sw|sv|zh-TW|th|tr|uk|vi|cy|yi)/archive/index.php/(.*)?$ archive/index.php?/$2&language=$1 [L,QSA]
RewriteRule ^/?(af|sq|ar|be|bg|ca|zh-CN|hr|cs|da|nl|en|et|tl|fi|fr|gl|de|el|iw|hi|hu|is|id|ga|it|ja|ko|lv|lt|mk|ms|mt|no|fa|pl|pt|ro|ru|sr|sk|sl|es|sw|sv|zh-TW|th|tr|uk|vi|cy|yi)/$ index.php?language=$1 [L,QSA]
RewriteRule ^/?(af|sq|ar|be|bg|ca|zh-CN|hr|cs|da|nl|en|et|tl|fi|fr|gl|de|el|iw|hi|hu|is|id|ga|it|ja|ko|lv|lt|mk|ms|mt|no|fa|pl|pt|ro|ru|sr|sk|sl|es|sw|sv|zh-TW|th|tr|uk|vi|cy|yi)/(.*)?$ $2?language=$1 [QSA]

I'm sure it's a setting I've configured wrong somewhere, but can't figure out where. Any ideas?

EDIT: Disabled SEO for now as I'm running into a few other issues with it.