WmTomcat throwing error while loading

Hi,

I am using webMethods 7.1.1 to run a web Application package having dependency on WmTomcat package. But while loading packages on server start, IS is throwing error as

[ISS.0028.0012I] WmTomcat: Startup service (wm.tomcat.admin:startup)
[ISS.0100.0008I] java.lang.NoClassDefFoundError: org/apache/commons/modeler/modules/MbeansSource
[ISS.0028.0013E] Startup service exited with the following error: com.wm.app.b2b.server.ServiceException: java.lang.NoClassDefFoundError: org/apache/commons/modeler/modules/MbeansSource

This class is coming from the jar file
\packages\WmTomcat\code\jars\commons-modeler.jar

I checked in this folder if this file is missing but it’s there.

Can anybody guide me where it is going wrong?

Below is the details of the IS:

Version 7.1.1.0
IS_7-1-1_SrvPrtcl_Fix5
IS_7-1-1_WebSvcsXML_Fix4
IS_7-1-1_Core_Fix5
IS_7-1-1_Audit_Fix1
IS_7-1-1_PubSub_Fix2
Build Number 134
Java Version 1.5.0_12 (49.0)
Java VM Name Java HotSpotâ„¢ Client VM
Java Build Info 1.5.0_12-b04, mixed mode
OS Linux
OS Platform i386
OS Version 2.6.9-42.0.8. Red Linux EL

Thanks in advance.
Sunil