SNAP messes up my xml sitemaps

Hi all

My debugger says:

Warning: preg_match_all() [function.preg-match-all]: Compilation failed: unrecognized character after (?< at offset 3 in:

var/www…./wp-content/plugins/social-networks-auto-poster-facebook-twitter-g/nxs_functions.php on line 897

I noticed that my sitemaps that are generated by Yoast’s SEO plugin appear blank but when I checked the source of the sitemap_index.xml page is gives the same error at the bottom of the page.

Any ideas?

John

http://wordpress.org/plugins/social-networks-auto-poster-facebook-twitter-g/