Thanks for investigating so fast! Indeed, it seems to be a connectivity problem,
since today, the mirror is working. Murphy... the last days (!) it never worked
for us. :/

Is there any option of editing the timeout for a specific mirror?

I just scanned the mirror successfully:

...

Mon Jun 18 23:53:00 2012 mirrors.ibiblio.org: scanned 6088 files (9/s) in 656s
Mon Jun 18 23:53:00 2012 mirrors.ibiblio.org: purging old files
Mon Jun 18 23:53:00 2012 mirrors.ibiblio.org: files to be purged: 0
Mon Jun 18 23:53:01 2012 mirrors.ibiblio.org: total files after scan: 6088 
(delta: 6023)
Mon Jun 18 23:53:01 2012 mirrors.ibiblio.org: purged old files in 1s.
Mon Jun 18 23:53:01 2012 mirrors.ibiblio.org: done.
Completed in 10.9 minutes

This mirror seems to be slow. Slow to scan and slow to serve files. It used to be 
better in times, but I remember it also being very slow in the past. It's simply 
a large, popular and very loaded mirror. 

Scanning with `mb scan ibiblio -vvvv` shows that the scan works, I suppose it 
might not have finished because it ran into a timeout at some point in the 
process? Or the mirror wasn't responding intermittently. Did you see the error 
several times?

For some days, the MirrorBrain parser seems to have issues parsing

http://mirrors.ibiblio.org/tdf/

dirs --missing libreoffice is positive, and mb scan results in
"http://mirrors.ibiblio.org/tdf/libreoffice/?F=1: error "500 Can't connect to
mirrors.ibiblio.org:80 (connect: Verbindungsaufbau abgelehnt)" fetching index,
skipped."