Resolution:
BE 2.0 Debugger cannot be started either inside Designer or from the command line and the following exception is thrown:

java.lang.NullPointerException
        at com.tibco.be.ui.tools.BEToolFrame$4.dockableFrameHidden(Unknown Source)
        at com.jidesoft.docking.DockableFrame.fireDockableFrameEvent(Unknown Source)
        at com.jidesoft.docking.DefaultDockingManager.t(Unknown Source)
        at com.jidesoft.docking.DefaultDockingManager.a(Unknown Source)
......

Resolution

======= 

This is a known issue and has been addressed in BE 2.0 hotfix1. After applying BE 2.0 hotfix1, the user needs to add the hotfix/lib and its subdirectories to the ${TIBCO_HOME}/be/2.0/bin/be-tools.tra file.

On Windows
========
- Replace the value of tibco.env.CUSTOM_CP_EXT with %BE_HOME%/hotfix/lib;%BE_HOME%/hotfix/lib/palettes;%BE_HOME%/hotfix/lib/ext;%BE_HOME%/lib;%BE_HOME%/lib/palettes;%BE_HOME%/lib/ext;%HAWK_HOME%/lib;%BW_HOME%/hotfix/lib;%BW_HOME%/lib;%BW_HOME%/lib/palettes;%TRA_HOME%/lib/palettes;%TPCL_HOME%/uddi4j/lib/uddi4j.jar;%TPCL_HOME%/jviews/6.0;%TPCL_HOME%/jviews/external

Example:

tibco.env.CUSTOM_CP_EXT %BE_HOME%/hotfix/lib;%BE_HOME%/hotfix/lib/palettes;%BE_HOME%/hotfix/lib/ext;%BE_HOME%/lib;%BE_HOME%/lib/palettes;%BE_HOME%/lib/ext;%HAWK_HOME%/lib;%BW_HOME%/hotfix/lib;%BW_HOME%/lib;%BW_HOME%/lib/palettes;%TRA_HOME%/lib/palettes;%TPCL_HOME%/uddi4j/lib/uddi4j.jar;%TPCL_HOME%/jviews/6.0;%TPCL_HOME%/jviews/external

On Unix/Linux:

- Replace the value of tibco.env.CUSTOM_CP_EXT with %BE_HOME%/hotfix/lib:%BE_HOME%/hotfix/lib/palettes:%BE_HOME%/hotfix/lib/ext:%BE_HOME%/lib:%BE_HOME%/lib/palettes:%BE_HOME%/lib/ext:%HAWK_HOME%/lib:%BW_HOME%/hotfix/lib:%BW_HOME%/lib:%BW_HOME%/lib/palettes:%TRA_HOME%/lib/palettes:%TPCL_HOME%/uddi4j/lib/uddi4j.jar:%TPCL_HOME%/jviews/6.0:%TPCL_HOME%/jviews/external

Example:

tibco.env.CUSTOM_CP_EXT %BE_HOME%/hotfix/lib:%BE_HOME%/hotfix/lib/palettes:%BE_HOME%/hotfix/lib/ext:%BE_HOME%/lib:%BE_HOME%/lib/palettes:%BE_HOME%/lib/ext:%HAWK_HOME%/lib:%BW_HOME%/hotfix/lib:%BW_HOME%/lib:%BW_HOME%/lib/palettes:%TRA_HOME%/lib/palettes:%TPCL_HOME%/uddi4j/lib/uddi4j.jar:%TPCL_HOME%/jviews/6.0:%TPCL_HOME%/jviews/external

TIBCO BusinessEvents (BE) 2.0 Debugger cannot be started either inside Designer or from the command line and throws a NullPointerException.