Is it necessary to create the Watching Only Wallet? cause it is complicated, I don't really know how to do it?
No, you don't need to create a watching only wallet.
How to import watch only? the pop up message says 'same name file'.
You can't import a watching only wallet for a wallet which is already in Armory. You already have the same wallet in Armory which is probably your non-watching only copy of it. That's fine and you can access and spend your Bitcoin.
I always got this message says 'failed to spawn db', what is this means? should I do anything about it?
It means that ArmoryDB, the database backend process, is not starting.
bitcoinarmory.com is not Armory's website anymore. There is no Armory contact email. If you want help, you will need to post here.
What should we do if BIP48 introduced on 1 Aug? Is Armory supporting it? Is our Bitcoin saved in Armory wallet affected? Any action needed?
Armory will use whichever chain that your Bitcoin Core install uses. If that is BIP 148, then it will use BIP 148. If it is not, then it will not use BIP 148.
