Zend Extension Manager error

[ubion]

Web Serivice is stopped at the point that zem.log starts as follows

We got the sample problem with Zend Server CE version.
This is why we decide to buy Zend Server 5.6 License.

What make it this kind of error?
What's the problem?

Server Spec.
HOST moodle3
Model HP DL380G6
CPU Intel(R) Xeon(R) CPU E5530 @ 2.40GHz 4core*2 = 8core, 8MB Cache Memory
RAM 8GB
HDD 146GB * 3, RAID 5, 293GB
O/S CentOS 5.8 final 64bit (Linux moodle3 2.6.18-308.el5 #1 SMP Tue Feb 21 20:06:06 EST 2012 x86_64 x86_64 x86_64 GNU/Linux)
S/W Zend Server 5.6.0 (Apache 2.2.22, PHP 5.3.14) , Apache Tomcat 6.0.9, JDK 1.6.0_32

[idobms]

There are a few crashes in the log and it looks like most of the crashes are during shutdown in one of the extensions. The extension manager logs the error but the crash seems to be inside libphp5 probably in one of the extensions.