Page is a not externally linkable
-- Google SEO News and Discussion
---- Increase in not found errors message in webmaster tools
levo - 1:29 pm on Jan 8, 2013 (gmt 0)Thread source:: http://www.webmasterworld.com/google/4534213.htm
Since you're deleting the pages and there is no mistake, you can safely ignore the message.
Redirecting visitors to the home page would be a soft-404. [support.google.com...]
Brought to you by WebmasterWorld: http://www.webmasterworld.com