Alright. I'm using a outdated version of wine, I'm updating to 1.3 now.
As far as your cd problem, linux is case sensitive.
So, you could probably just do a
cd Downloads
and that will put you in your downloads folder.
Edit: updated, I have steam installed now. downloading CS:S, going to be a while though. In the meantime, can you start steam ok? Also, if you can, disable in game community under settings.