erm im in webmaster tool and as google did new crawl on my site on 13th of march - question I have is , it says one url is not found, i checked the url and its an Old flash banner I use to have on my front page while sit was not open. however, that file no longer is on my site, nor is it in my ftp . Why is it saying link not found?

Because you deleted the file in question and either you still have a reference to it or had one as of March 13.

Best thing you can do is to find a text editor with an extended find tool (e.g. Notepad++) and see if you can find the reference to the file.

The other thing could be your site was down for some time and google could not find it. Mine was down for some DDoS attack on godaddy server and google reported the same as not found.

may be not yet added