Resolution:
Assuming that BW 5.1.2 installation on Solaris 2.8 performed by root:

--If you are starting DomainUtility using user account other than 'root'
it will have an immediate effect on the DomainUtility's available options.

For example, there no longer will be the option to create a New Domain for the user
(it is still available if you are using 'root' account), meaning that functionality is reduced.

There will be additional issues involved, for example, Administrator may not recognize the installed application and you cannot deploy any application.

This is currently by design.  
If you like to use a different user to start the process you should create a softlink to the vpd files in the user home directory for the specific user.

Using DomainUtility from a user account that is different from the user that installed TRA/Administrator