Why does this mod to my htaccess file bomb vbulletin

[wacnstac]

I'm adding some lines to enable VBSEO. My .htaccess file in my forum root is as follows:

RewriteEngine On
RewriteRule ^((urllist|sitemap).*\.(xml|txt)(\.gz)?)$ vbseo_sitemap/vbseo_getsitemap.php?sitemap=$1 [L]
<IfModule mod_security.c>
SecFilterEngine Off
SecFilterScanPOST Off
</IfModule>

When I make this modification
really bad things happen

[Zachery]

How does it "bomb" your site?

[wacnstac]

I get permissions errors on every vbulletin page.

[wacnstac]

Forbidden

You don't have permission to access /forum/showthread.php on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

[Steve Machol]

Does it do this without your vBSEO changes?

[wacnstac]

Steve,

I have done so far is to copy the vbSEO changes to a subdirectory under my main forums directory. I have yet to install the product.

[Steve Machol]

Yes, but if I understand you correctly it was working then you made a change and it stopped working. The ssolution is to undo whatever change you made.