|You should be able to have multiple printers installed. I currently have three printers installed and working. Only one of them is wireless and it is networked.|
If an installation has failed the first time, you need to remove any reference to that failed attempt or subsequent attempts may fail.
Are you following the instructions for the Brother step by step?
When installing a wireless unit, it is usually easier to install it wired first and the printer will then HELP you setup the wireless features. After that you just don't need to keep the USB cable connected.