Mail error Question

Any idea why I am getting this error in a mail in my box? Thanks, Sid ----- The following addresses had permanent fatal errors ----- <sako-O05NZe1qxicxnA8XTFIEbw at public.gmane.org> (reason: can't create (user) output file) ----- Transcript of session follows ----- procmail: Quota exceeded while writing "/var/spool/mail/sako" 550 5.0.0 <sako-O05NZe1qxicxnA8XTFIEbw at public.gmane.org>... Can't create output