Problem with Sitemaps and SEO plugin

Hey guys, I installed Sitemaps and SEO plugin from this site, all blogs seems to work fine with /sitemap.xml except the main site.
when I try to access domain.tld/sitemap.xml it gets me a sitemap but its an invalid XML with an empty line on the top (again all other blogs are fine.)
I checked the cached sitemap.xml which is fine - no new line chars at the top. After debugging a bit I realized its when adding "require( '../wp-load.php' );"
in sitemap.php

And this problem is only on the main blog, any ideas?