For 0.96.5, the argument is "fcgi-port". Please stick to that version.
Are you running ArmoryDB manually? If so either add the arg to your command line:
ArmoryDB.exe --fcgi-port=14000
You can set this either in the target for a shortcut of ArmoryDB.exe, or when you spawn the DB from the command line. 14000 is just a stand in value to show what the full argument looks like, use whatever value you want. Keep in mind you need admin privileges to use ports below 1024.
You can also use the config file. Add this line to armorydb.conf:
This config file can be found in your datadir (where you wallets are). If you do not see the file there, create a plain text file and name it accordingly.
If you let ArmoryQt spawn the db for you, it will randomize the port to a value within [49150, 64150]