Quote Originally Posted by bplex
More information is needed to be able to help you (such as what map are you presenting to Google)?

As for the 404 errors, a 404 is a file not found error. This means that Google is being told that you have 300+ files that do not exist on your server.
Thanks. I am using Google webmaster tool to monitor my site and this is the first time i am seeing this errors. And only 1 url/file is not found. I have no site map. This result is from Googlebot crawls.