Unable To View workflow Status Diagram

In a fresh R12 installed instance, When clicked on the Status diagram following message appears "You have encountered an unexpected error. Please contact the System Administrator for assistance."

When pressed on the click Here link the below error message displays:
oracle.apps.fnd.framework.OAException: java.lang.NullPointerException ( and it displays lot of lines with the exception message)

Solution:

Set the profile option Server Timezone at Site level (should be set to the value of database timezone) and Bounce the Apache Server