i was just reading this over ...where it is showing the post name ..that looks like eithersetting in vbulletin 4. I have seen vbulletin 4 built is seo cause issues. I would shut that off first or change how it is behaving. I would do this before i would do any .htaccess rules.
it is in vbulletin options - server setting and optimization settings
I would actually go there and set friendly urls to standard urls and see if that fixes your issue. I think it will..
If not it is one of those settings in friendly url or somewhere in that section.
Legend!! This solved it :-)
MANY, MANY, MANY THANKS!!
I ended up having to change the following to get it to work properly.
URL Type
Enabling friendly URLs can increase your site's ranking in search engines. = Advanced Friendly URLs
Enforce Canonical URL
This options defines how canonical URLs are enforced for guest users (including search engines).
If Standard is selected then guest users will be redirected to the correct URL if they request a page using the wrong Friendly URL format.
If Strict is selected then guest users will also be redirected to the correct URL if they request a page using the wrong text. This may also include requesting URLs in the wrong character set. = STRICT
Vbulletin -> Settings -> Friendly URLs
Would it also be handy to have the above stuff in the .htaccess file, or do you think that it is overkill (of a good policy to follow)?