My Linux browser is Firefox. When I ask it to go to 10.1.1.1, I'm prompted for the user name and password and I give those and press Enter. Then, the browser says that it's waiting for 10.1.1.1 and never connects.
1) I have the same modem. It's not possible to configure this modem (beyond the basic username/password level) using any web browser except Internet Explorer. Firefox should connect eventually (after about two minutes), but when you try to add forwarding rules or any other of the forms except for the most basic configuration you'll get "Method Not Supported" errors. You could (in theory) reconfigure everything from the telnet interface. Good luck finding any documentation though.. 3) Any changes you make to the modem via Windows will still be active when you boot back to Linux. If you have Windows installed, that's probably the easiest way to reconfigure your modem.