I too have a connection problem, but it's different from the others recently reported.
I use LXDE on my Dell inspiron mini 10 v and update it frequently. At home I use mac address filtering on my router and don't have a password, but I'm visiting my son for Christmas and he does use a password. It was OK last time I visited but won't connect now. Yesterday morning at home before we left I had no problem. I can detect his router and several neighbouring ones, but cannot connect. I'm guessing, but I think the password is not being sent correctly. The password type is WPA/WPA2 Pre-shared key.
I still have two older installations on this machine: a much updated LXDE 2010 abandoned earlier this year for the 2012 version and a much older KDE3 installation. Both of these will connect to his system without any problem..
After using the 2010 version to check the internet and my e-mail I foolishly decided to upgrade Firefox and Thunderbird from versions 12 to versions 17 as I was getting security risk messages. Firefox worked OK but Thunderbird has disappeared, it won't start up at all. This means that I have to go to the version 2.0 on the KDE3 installation to see my email. All this would be solved if I could use the latest version.
Some of my latest files are only available on my 2012 version; I am using the 2010 version for posting this and I have to use KDE3 for e-mail.
I've tried removing and reconnecting dozens of times. all the parameters seem to be the same on the software in the 2012 and 2010 versions and are the defaults.