[CentOS] Problems with logwatch under CentOS 6.3

Hi all,

 Last week I have migrated 5 CentoS 6.2 servers to CentOS 6.3. In all
of them, I receive every day problems with logwatch:

/etc/cron.daily/0logwatch:

Can't exec "sendmail": No such file or directory at /usr/sbin/logwatch
line 1040, <TESTFILE> line 1.
Can't execute sendmail -t: No such file or directory

 It is really strange, because I am using default config ... On the
other side, I have three CentOS 6.2 servers and these problems doesn't
appears ...

 How can I debug this??

 Thanks.