What could this be? Transfer error code 16

[Boniforti Flavio]

Hy people, where could this be coming from?

rsync: send_files failed to open "Alfredo Polti
SA/wz_ALFREDO_POLTI_SA.ac0" (in Winway_z-32): Device or resource busy
(16)
rsync: send_files failed to open "Alfredo Polti
SA/wz_ALFREDO_POLTI_SA.ac3" (in Winway_z-32): Device or resource busy
(16) rsync error: some files/attrs were not transferred (see previous
errors) (code 23) at main.c(1524) [generator=3.0.5]
WARNING: Some files and/or directories in localhost::Winway_z-32/ only
transferred partially during rsync operation

Flavio Boniforti

PIRAMIDE INFORMATICA SAGL
Via Ballerini 21
6600 Locarno
Switzerland
Phone: +41 91 751 68 81
Fax: +41 91 751 69 14
Url: http://www.piramide.ch
E-mail: flavio at piramide.ch