I am running Version 5.0.10_GA_2638.UBUNTU8.FOSS Oct 3, 2008.
In my /tmp/gengraphs.out file I have the following line listed over and over:
/opt/zimbra/zimbramon/rrdtool/bin/rrdtool: /lib/libc.so.6: version `GLIBC_2.7' not found (required by /opt/zimbra/zimbramon/rrdtool/bin/rrdtool)
I am digging into this because my stats graphs all show "Data not yet available"
Everything else with the server seems to be running fine. If I need to provide more information to help diagnose this please let me know.