.htaccess subdirectory redirect with non www to www and parameters - apache

Question

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /qsg/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?Item=$1 [L]
</IfModule>
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /qsg/
RewriteCond %{HTTP_HOST} ^example\.com [NC]
RewriteRule ^ http://www.%{HTTP_HOST}%{REQUEST_URI} [L,R=301]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?Item=$1 [L]
</IfModule>
I tried to look for an answer, but haven't been able to find one.
I am trying to redirect:
http://example.com/qsg/abcd
to
http://www.example.com/qsg/index.php?Item=abcd
I can get this working fine when the www is present in the URI. When I remove the www, it redirects to http://www.example.com/404.shtml
I've tried the two methods above with both the same result. I just can't figure out what I am doing wrong. I've seen plenty of other examples where this should work, but not for me. Do I have something wrong in my .htaccess file is there a possibility of something else causing the bad redirect?
Note: both the above rewrites are not included in the file. I've tried both independently.

Answer 1

Give this one a shot:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /qsg/
RewriteCond %{HTTP_HOST} !^www\. [NC]
RewriteRule ^(.*)$ http://www.%{HTTP_HOST}/$1 [L,R=301]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php?Item=$1 [L,PT]
</IfModule>