I think datasheets have been discontinued -- I've been getting the crawl errors also -- just mark all of them as 'fixed' -- this happens whenever a site discontinues some pages. sometimes you can solve this by redirecting to an active page, but in this case, it's better to eliminate thousands of pages
i'm still dealing with phantom links from gallery2 which I eliminated several years ago; it's just the price we pay for trying new things.
meanwhile, sym has rocketed my sites, syn AND non-sym up over a million places in alexa rankings. and my sym site just jumped over pond5 to become my 2nd best earner so far this month! those $10 sales really add up compared to the $.25 earnings from the bottom feeder sites. if this becomes a trend I can cut my site submissions from 12 down to 3 or 4 at most