When I try to enter a Username and password or anything for that matter on that screen, nothing happens. I click the box, it highlights, but when I type, nothing gets entered. And by not allowing me to enter in a password, I can't join a game. The game lets me reassign button commands in the options, but that's all.
Any help please?

What sort of keyboard layout do you have? I take the inability to write text in RWR also affects campaign username and savegame name fields, and also chat (by default press enter in-game)?

QWERTY. I can start a campaign with the default username (Mr. Green) And I can press enter in-game, and type just fine. Moving around and all that works just fine. The problem is that it wont let me change text in any of the fields when starting a campaign, or joining a multiplayer server.

That's certainly weird in that case, and it's the first time I've heard of someone having this sort of issue.

It's on Windows, yeah?

Yeah. I even tried a different keyboard, and still no luck. Probably going to have to get a refund from steam before the time expires.

I'd say go for it for the refund. I can't make debug builds currently as most of my equipment is at a temporary storage due to water damage in the house we were supposed to move into a week ago, and it'll take at least until next month for the next chance.