For what it's worth, I'll just post a "me too".
Fresh install of 4.5.7, not an upgrade
I did a yum install sysstat which seemed to make zmcontrol status show the stats service as running.
However, I still have the problems mentioned by everyone else, namely -
1. I only seem to get anything interesting in the Admin interface stats page if I run zmgengraphs and such by hand, and even then I don't seem to get everything.
2. I *NEVER* get any AS/AV stats. Sadly, that's really one of the main reasons I was upgrading to Zimbra was to improve spam blocking and to keep track of those kinds of stats better.
Surely they can't only put the fix in 5.0? An upgrade is far too dangerous and time-consuming for me to do right after upgrading to 4.5.7 just recently!