How do I fix error 11001 so that I could send email on craigslist.com I'm having a problem with pop3.please help me.

verify that the hostname/ip and the port are correctly written in the fields. No spaces in front etc. Also try using an direct IP instead of hostnames. Also, try going to settings, windows update.

See if this helps
How to deal with Outlook Express error 0x800ccc0d or 0x800ccc0e (http://www.tiscali.co.uk/help/email/oe_errors_0x800ccc0e.html)