[Dovecot] Dovecot Antispam - Unable to determine the runtime user

[lodan]

Hi all,

I have a small problem with the dovecot-antispam plugin. When I try to
move a message to my spam folder, I have this error:

IMAP4> 149 UID COPY 15 SPAM 
IMAP4< 149 NO [CANNOT] Failed to call dspam

And in the server log file:

mail dspam[12339]: Unable to determine the runtime user

I'm running dspam 3.9.0 with dovecot+managesieve 1.2.10 and
dovecot-antispam git (2010-03-22).

Thanks for your help
Best regards