WordPress MU

Hello,

I installed the Sitemaps and SEO - WPMU Style plugin but am getting errors in http://example.com/sitemap.xml and also all the subdomain blogs on my WPMU site.

The error looks like this (below the error the rest of the info seems to show correctly):

Warning: file_put_contents() failed to open stream: Permission denied in /home/xxxxxxx/public_html/wp-content/mu-plugins/simple-sitemaps.php on line 230

Warning: Cannot modify header information - headers already sent by (output started at /home/xxxxxxx/public_html/wp-content/mu-plugins/simple-sitemaps.php:230) in /home/secretgf/public_html/wp-content/sitemap.php on line 43

Plugins installed:

in /wpmu-plugins/

Blog Defaults
Google Analytics for WPMU
Sitewide Tags

in /wp-content/plugins/

All in One SEO Pack
Custom Headers and Footers
Simple Post Thumbnails
Yet Another Related Posts

I didn't post this question over at wpmudev because my subscription expired and I'm not in the position to renew at this moment. Thank you.

I'd like to add that I already added the necessary line to my .htaccess file in the correct place RewriteRule ^(.*/)?sitemap.xml wp-content/sitemap.php [L]

I also checked that there are no white spaces in the beginning or end of the php files with the errors.

Here's an excerpt of the files with the line #s

simple-sitemaps.php

227   // Open the file for writing
229   if (($fh = @fopen($filename, $mode, $use_inc_path)) === false) {
229        user_error('file_put_contents() failed to open stream: Permission denied',
230            E_USER_WARNING);
231       return false;
232    }

sitemap.php

41	$content = $Incsub_SimpleSitemaps->GenerateSitemap( $wpdb->blogid );
42
43	header( 'Content-type: text/xml; charset=utf-8' );
44	echo $content;
45
46	echo "\n<!-- Sitemap was generated for this view -->";