I'm fairly a n00b on htacess and this one's thrown me for a loop. Mostly all I've done are simple 301's and correcting minor errors I've encountered. I also usually have access to the server so I can test by trial and error and learn that way. In this particular case every time I want to try a code change, I have to submit a support ticket.. big hassle :-)
Anyways, the problem I'm having is with a shopping cart system called CoreCommerce.
This URL is generated by the cart: [mysite.com...]
Both of those URL's are valid. Both are generated. But they both exist and it's creating duplicate content issues across Google. Every single item in the store has both URL's indexed and we are now getting links to both and we really just want the bottom one.
Only every use the .* pattern if it is the LAST item before the $ end anchor.
Make sure the non-www to www redirect is the LAST redirect in the list of redirects otherwise you will generate an unwanted multi-step redirection chain for some requests.
The mixed-case patterns are best done with the [NC] flag, and not [Ww][Or][Rr][Dd].
Don't forget to escape all literal periods in patterns.
Every redirect needs the [R=301,L] flags. Every rewrite needs the [L] flag.
Every wildcard part of every rewritten request must be validated other wise malicious links of the form example.com/this-product-is-junk-902462-acme-widget will result in your content being indexed for these "spoofed" URLs.
I can't see what else you want to change. You must use example.com in your question in order to stop forum auto-linking.