"broken pipe"

what is a broken pipe and why is it happening?
takes about 20 seconds of nothing and then the "broken pipe" posting comes along.

also, when I went to the support page to check, I get this message from clicking on Knowledge Base:

Database error:Invalid SQL: SELECT f.id as id, fs.name as name FROM file as f, filesystem as fs WHERE fs.fileid=f.id ORDER by f.created DESC LIMIT 5
MySQL Error: 145 (Table '.\kb\file' is marked as crashed and should be repaired)
Session halted.

the 'Knowledge Base' page