Description of problem:
It is impossible to open most of the Guided rules, that are part of the BPM Example Application (BigApp).

The following errors are shown:
Unable to complete your request. The following exception occurred: java.lang.ClassNotFoundException:org.apache.commons.lang.StringUtils from [Module "org.drools:main" from local module loader @6fb75649 (finder: local module finder @6d820beb (roots: /home/jhrcek/Servers/CR2/modules,/home/jhrcek/Servers/CR2/modules/system/layers/bpms,/home/jhrcek/Servers/CR2/modules/system/layers/base))].

For other GREs it shows this error:
Unable to complete your request. The following exception occurred: java.lang.NoClassDefFoundError:org/apache/commons/lang/StringUtils.

There are no exceptions in server.log

Version-Release number of selected component (if applicable):
BPMS 6.0.1 CR2

How reproducible:
Always

Steps to Reproduce:
Follow standard steps to install bigApp:
1. In business central login as admin (to be ablo to clone big app git repo)
2. go to: Authoring > Administration
3. go to: Repositories > Clone repository

Fill the required fields:
repo name: anything
Org unie: anything
file:///home/jhrcek/BigApp/jboss-bpm-example-dist-6.0.1.GA-redhat-4/mortgage-demo/.git
(repo is clone successfully)

4. go to: Authoging > Project Authoring
5. Navigate to MortgageApplication project, expand packages and try to open any of the Guided Rules (e.g. Jumbo Mortgage)

Actual results:
Modal with error is shown (see Description)

Expected results:
Guider rules should open successfully

Additional info:
There are no exceptions in server.log

Use
jboss-bpms-6.0.1.GA-redhat-4-deployable-eap6.x.zip (BigApp)
jboss-bpm-example-dist-6.0.1.GA-redhat-4.zip (BPMS 6.0.1 CR2)
from here, to reproduce the issue: http://dev138.mw.lab.eng.bos.redhat.com/candidate/bpms-6.0.1-CR2/