Errors with Google Sitemap

After installing vBSEO and running the generator I resubmitted my sitemaps to Google and it tells me this warning:

Unsupported file format
Your Sitemap does not appear to be in a supported format. Please ensure it meets our Sitemap guidelines and resubmit.

Do you have default vBSEO .htaccess file in your forums folder?

My .htaccess:

Code:

# Comment the following line (add '#' at the beginning)
# to disable mod_rewrite functions.
# Please note: you still need to disable the hack in
# the vBSEO control panel to stop url rewrites.
RewriteEngine On

# Some servers require the Rewritebase directive to be
# enabled (remove '#' at the beginning to activate)
# Please note: when enabled, you must include the path
# to your root vB folder (i.e. RewriteBase /forums/)
#RewriteBase /

#RewriteCond %{HTTP_HOST} !^www\.yourdomain\.com
#RewriteRule (.*) http://www.yourdomain.com/forums/$1 [L,R=301]

RewriteRule ^((urllist|sitemap_).*\.(xml|txt)(\.gz)?)$ vbseo_sitemap/vbseo_getsitemap.php?sitemap=$1 [L]

RewriteCond %{REQUEST_URI} !(admincp/|modcp/|cron|redir\.php)
RewriteRule ^((archive/)?(.*\.php(/.*)?)?)$ vbseo.php [L,QSA]

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !^(admincp|modcp|clientscript|cpstyles|images)/
RewriteRule ^(.+)$ vbseo.php [L,QSA]

####Charset
AddDefaultCharset Off 

####Gzip
<IfModule mod_rewrite.c>
RewriteCond %{REQUEST_FILENAME} -f
RewriteRule ^(.*)(js|css)$ redir.php?file=$1$2&type=$2 [L]
</IfModule>

####ETags
FileETag None

####Expires
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/gif A2592000
ExpiresByType image/jpeg A2592000
ExpiresByType image/png A2592000
ExpiresByType application/x-shockwave-flash A2592000
ExpiresByType text/css A2592000
ExpiresByType application/x-javascript A2592000
</IfModule>

Please open a ticket with ftp access for troubleshooting.

Ticket 9962 submitted.

I'm getting 404 errors even after I uncommented the RewriteBase