lucy24 - 4:49 am on Jan 21, 2012 (gmt 0)
Why are you spending time in your ERROR log? Those entries have already been handled by the server and do not constitute significant bandwidth traffic on your site. Look at your active server logs to see if you can find any kind of pattern to the entries in the error log...which might provide info regarding scrapers, mal-links, etc. Better place to spend your time. The error.log is links already dealt with.
This isn't always true. A 403 in your access log generally means door slammed in their face, "client denied by server configuration", end of story. But it can also mean that you goofed in your .htaccess and the 403 is the end result of an infinite rewrite with the server saying Enough Is Enough after (generally) ten iterations. If this is the case you do need to take the occasional look in the error log, find and isolate the problem.
Is anyone having trouble figuring out how I know this?