When I installed Google XML Sitemaps, I recieve the following error, every tiime
Warning: filemtime() [function.filemtime]: stat failed for /home/username/public_html/blog/sitemap.xml in /home/username/public_html/blog/wp-content/plugins/google-sitemap-generator/sitemap-ui.php on line 504
# Your sitemap was last built on December 31, 1969 6:00 pm.
Warning: filemtime() [function.filemtime]: stat failed for /home/username/public_html/blog/sitemap.xml.gz in /home/username/public_html/blog/wp-content/plugins/google-sitemap-generator/sitemap-ui.php on line 513
what do these errors mean? I have tried rebuilding the sitemap.xml file, and I keep getting this exact same error. is it an error writing to the server or what?