[marcmac]

Any errors in /var/log/zimbra.log or /opt/zimbra/log/zimbra.log around the time these were received?

Also:

[shell]# rpm -qa | grep compat-lib
compat-libstdc++-33-3.2.3-47.3
compat-libstdc++-296-2.96-132.7.2

you got those installed?