[Dovecot] Dovecot sieve redirect: failed to redirect message to user at domain.com

[Thiago Henrique]

Hello,

I'm running Dovecot 2.0.13 on my Ubuntu10.04. It's working very well but
I faced a problem with Redirect and Vacation using Sieve. :-(
In fact, after well configuring the system I dont't receive the redirect
message, and in the log I found:

########################################################################################
Jun  9 18:49:37 box7 dovecot: lmtp(10734, user at server.com): Fatal:
execv(/usr/sbin/sendmail) failed: Permission denied
Jun  9 18:49:37 box7 dovecot: lmtp(10734, user at server.com): Error:
Sendmail process terminated abnormally, exit status 84
Jun  9 18:49:37 box7 dovecot: lmtp(10734, user at server.com): Error:
At35JIgC8U3uKQAAndgVeA: sieve:
msgid=<20110609184850.0FAB8200A41C at domain.com>: failed to redirect
message to <user-destination at server.com> (refer to server log for more
information)
########################################################################################

In sieve.log I see:

########################################################################################
error: msgid=<2011060919.0200A375 at domain.com>: failed to redirect
message to <user at domain.com> (refer to server log for more information).
########################################################################################

Manually sendmail command works normally. Cron sends email normally.
Any idea about the reason this happen and how to solve?

Thanks in advance,
Thiago Henrique