[KrisP]

I changed web hotel and now I get

Forbidden
You don't have permission to access /index.php on this server.

To give an example I found out that changing

ErrorDocument 404 /index.php

to

ErrorDocument 404 http://www.mydomain.dk/index.php

solved the problem for that line, but

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

is still causing the forbidden error
changing to

RewriteEngine On
RewriteRule ^(sitemap.*\.(xml|txt)(\.gz)?)$ http://www.mydomain.dk/vbseo_sitemap/vbseo_getsitemap.php?sitemap=$1 [L]

doesnt help - so what does the "full path version" of the rewrite look like ?