unable_to_chdir_to_maildir

[Deltoid]

I got this message every few seconds in /var/log/mail.info

Nov 21 15:55:07 p15199372 qmail: 1132584907.851735 new msg 16818913
Nov 21 15:55:07 p15198372 qmail: 1132584907.851891 info msg 16818913: bytes 1130 from <[email protected]> qp 1571 uid 72
Nov 21 15:55:07 p15198372 qmail: 1132584907.871849 starting delivery 1: msg 16818913 to local [email][email protected][/email]
Nov 21 15:55:07 p15198372 qmail: 1132584907.872008 status: local 1/10 remote 0/20
Nov 21 15:55:07 p15198372 qmail: 1132584907.886829 delivery 1: deferral: Unable_to_chdir_to_maildir._(#4.2.1)/
Nov 21 15:55:07 p15198372 qmail: 1132584907.886989 status: local 0/10 remote 0/20

can anyone help me