Sitemap help

Hello 

i submit site map for . but here is 1 error (warning ) please help me :

sitemap Warning : When we tested a sample of the URLs from your Sitemap, we found that some URLs were not accessible to Googlebot due to network timeouts. If this problem persists, please check the network availability of your DNS and web servers. All accessible URLs will still be submitted. 

and my this website keywords : 

Old == Google.Com == top 31

and 

after new ===Google.Com--Not in 100

what is its means please help me .

--
You received this message because you are subscribed to the Google Groups "Google Search Engine Optimization SEO Google - MSN - Yahoo" group.
To unsubscribe from this group and stop receiving emails from it, send an email to seo1+unsubscribe@googlegroups.com.
To post to this group, send email to seo1@googlegroups.com.
Visit this group at http://groups.google.com/group/seo1.
For more options, visit https://groups.google.com/groups/opt_out.