Hello David,
There are a few things that come to mind with that error message.
First is to follow the technote you referenced: http://support.veritas.com/docs/286488
Second is a possible problem with your Backup Exec database.
To test if your database is the culprit, create a new selection list with 3-4 items in it.
If you are able to save it, then it is possible that the registry entry you modified/created needs to be checked again.
It should be a DWORD named : MaxRpcDatablockSize
When entering the Value Data, make sure that the Base is set to Hexadecimal.
The data should contain only eight characters of the letter "F" ( FFFFFFFF ).
After making the change, restart your Backup Exec services.
Restarting the services can be accomplished from the Tools menu in Backup Exec, selecting Backup Exec Services.
