Newsyslog | Cronjob faulty?

[Jos Chrispijn]

At midnight (00.00) I run this cronjob from my crontab:

Crontab:
00              *       *       *       *       root    newsyslog

For some reason this goes wrong; (if I run 'newsyslog' on any other 
time, there is no error message).

bzip2: Can't open input file /var/log/maillog.0: No such file or directory.
newsyslog: `bzip2 -f /var/log/maillog.0' terminated with a non-zero 
status (1)

/var/log:
-rw-r-----  1 root    wheel     63162 May 16 21:20 maillog
-rw-r-----  1 root    wheel       109 May 16 00:00 maillog.0.bz2
-rw-r-----  1 root    wheel     73674 May 16 00:00 maillog.1
-rw-r-----  1 root    wheel       111 May 15 00:00 maillog.2.bz2
-rw-r-----  1 root    wheel     73050 May 15 00:00 maillog.3
-rw-r-----  1 root    wheel       109 May 14 00:00 maillog.4.bz2
-rw-r-----  1 root    wheel    184042 May 14 00:00 maillog.5

Can somebody tell me what goes wrong here?
On my other FreeBSD server the same cronjob goes ok...

thanks,
Jos Chrispijn