I got this error when start a full crawl in 2010 server.

Work Arround :

Open the web.config for the website 80. Find the line : identity impersonate="true"

If the identity impersonate is set to "false" (which create the error during the crawl), set up to "true".

Then run the crawl again. It completes now sucessfully.


NB: If you have more than one WFE, make sure you updated the all servers