.htaccess question

Hi

Not a regular here but have a .htaccess question.

I have two sites each running duplicate PHP pages and the .htaccess pages
are as follows

Site one...

---------
AddType application/rss+xml .rss
RewriteEngine on
# Change 'folder' to your base directory name
RewriteBase /
RewriteRule ^bmc-(.*)-(.*).html$ ?p=$1&id=$2
RewriteRule ^bmc-(.*)-(.*).jpg$ ?p=$1&id=$2.jpg
RewriteRule ^bmc-(.*).html$ ?p=$1
---------

and site 2

---------
AddType application/rss+xml .rss
RewriteEngine on
# Change 'folder' to your base directory name
RewriteBase /demo/
RewriteRule ^mcwd-(.*)-(.*).html$ ?p=$1&id=$2
RewriteRule ^mcwd-(.*)-(.*).jpg$ ?p=$1&id=$2.jpg
RewriteRule ^mcwd-(.*).html$ ?p=$1
---------

Site 2 .htaccess page works fine

Site 1 .htaccess page used to work on a previous server but since moving it
to the same server as site 2 it fails to recognise the rewrite's.

the only difference is site 2 is setup with a sub dir and not the root dir
as site 1 is.

mcwd and bmc correctly named for the respective sites.

is RewriteBase / correct?
it has only been about 12 hours since the DNS's were set, but when i look at
the pages its pulling the info from the new DNS. Could the DNS's not being
resolved cause this problem, meaning it would work after 24-48 hours once
the DNS change has taken effect.

Any help would be gratefully received.
Alex