As far as my problem is concerned the good team at Symantec support have provided the following solution:
To resolve the SP2 installation error, please follow these steps on the Vault server:-
1. Add the following regkey folder, VaultKey, to: HKEY_CURRENT_USER\Software\KVS
Once the VaultKey folder is created it will be populated with a registry key called Default.
Give Default a value of 1
2) Run setup.exe again. This time, the background, installation screen will appear in Red.
3) When you receive the error message again, leave the error message on the screen and go to the command prompt. Manually register the .DLLs and .EXEs as detailed in the error message, using REGSVR32 to register the .DLLs and /REGSERVER for .EXEs, if any executables are listed.
4) When finished, click OK on the installation Window to complete the installation.
I have not tried this yet but will ASAP.