Hallo again, boys & girls.
I'm afraid I've done a very silly thing. In trying to install my printer (which isn't recognised, it seems...very odd; I've managed to convert the Epson .debs with 'tazpkg convert', following Aleksej's advice), I've accidentally entered my USERNAME & password into CUPS, rather than the ROOT name and password.
CUPS, of course, wants you to be 'root' to do any sort of admin-related stuff. As if that wasn't bad enough, before realising what I'd done, I went and said 'Yes', when FF asked if I wanted to remember the log-in stuff.
This means, of course, that every time I try and go into CUPS, I'm always logged in as 'user' (instead of root).....and every time, it refuses to let me do anything!!
Would I be right in thinking that the only way to cure this is to create a new user profile for FireFox.....and start all over again?