Resolution:
If the machine that is running Administrator Domain is NOT connected to internet, When you upload BWFB application (.ear) in Admin Domain and try to save configuration a "Null Pointer Exception" is thrown. This is because Administrator is trying to access java.sun.com to fetch few j2ee dtds and xsd files.

This is a known issue in PortalBuilder 5 application deployments with Admin 5.3 domain. BWFB also is based on PS 5.

Followiing is the workaround for this issue -

Option 1:
Enable Internet Connectivity for the machine where TIBCO Administrator has been Installed.

Option 2:
Make the DTDs'/XSD available locally and swizzle the hosts file.
1) The DTD files can be downloaded from http://java.sun.com/dtd [Download the eight files listed in the 'J2EE DTDs' table]

2) Download http://java.sun.com/xml/ns/portlet/portlet-app_1_0.xsd

3) Place all these files under your local WebServer's document directory (DTD's downloaded in step 1 under &ltWS_Doc_Dir>\dtd directory and XSD downloaded in step 2 under &ltWS_Doc_Dir>\xml\ns\portlet directory).

This is a webserver running on your machine at port 80. I am using the same Tomcat server (5.0.28) which is registered with Domain to deploy FB applications running at port 80. Otherwise you can use the webserver that is running on port 80 or install Apache Web Server or IIS, etc and copy these files respectively.

I copied DTD files to tomcat/webapps/ROOT/dtd and the XSD file to tomcat/webapps/ROOT/xml/ns/portlet

NOTE: on Unix you can't start tomcat with port 80 as non-root user. You will need to start tomcat to run on port 80 as root user. A non-super user can't use ports under 1024.

4) Update hosts file to map  java.sun.com to a localhost IP address where DTD's are hosted.
Edit hosts file with the following entry:
127.0.0.1    java.sun.com

This will resolve the NULL Pointer issue.

When deploying BWFB application (ear) in Administrator 5.3, "Null" Tab is created and NPE thrown instead of Application Tab in Admin Console