I have recently upgraded my site from EE 1 to EE 2 and it appears to have resulted in some of my .htacess rewrites to change the URL structure no longer working.

My original setup was this:

RewriteRule ^/?((403|404|About|Chat|Contact|Copyright|Search)(/.*)?)$ /Westeros/$1 [L]
RewriteRule ^/?((ASoIaF|Digest|Images|Login|Store|Updates|Westeros|member)(/.*)?)$ /index.php/$1 [L]
I've also tried this:

RewriteRule ^/?((403|404|About|Chat|Contact|Copyright|Search)(/.*)?)$ /index.php/Westeros/$1 [L]
RewriteRule ^/?((ASoIaF|Digest|Images|Login|Store|Updates|member)(/.*)?)$ /index.php/$1 [L]
There's a couple of different things going on and some work and some don't, in both of these scenarios.

1) http://www.westeros.org/Updates/ works fine. Updates is a template group.
2) http://www.westeros.org/Search/ does not work. Search is a template within the Westeros template group. It does work to access it as http://www.westeros.org/index.php/Westeros/Search/.
3) http://www.westeros.org/About/ does not work. About is a Page with its URI set to /Westeros/About/. It does work to access it as http://www.westeros.org/index.php/Westeros/About/.

I imagine there's been some internal changes in URL handling between EE 1 and EE 2, but I can't quite grasp how it could stop these rewrites from happening. Isn't a rewrite the first thing that gets done, so shouldn't EE be seeing the rewritten URLs and nothing else?