Looks like they are all secure. You can make an antenna that amplifies your wireless receiver so that you can pick up the wireless you are on more easily.

This is made out a pringles can and works really well.

It could be any numbers of reasons. So my answer is....

IT DEPENDS

(boring crap to follow that basically says you're screwed)

It could be a wireless capable unit that isn't connected to the internet but some schmo is just using it as a switch. A printer adapter that has wireless capabilities but isn't connected to the internet. Or some one may actually know WTF they are doing and setup some overly elaborate configuration that lets you connect to the wireless router but not actually allow routing to the internet without some extra credentials or even some one who set it up to not DHCP the dns and gateway info. You told us it doesn't work and there are a number of reasons why it might not. To many, in fact, to even begin to help you get over this little hump.

thaninja's idea is decent one given a couple of points. Can antennas like that typically do much better as a line of site antenna. So unless you know exactly where it is and can convince the other person to setup a similar device on their end (basically a high tech can-on-a-string method), you won't see much improvement.

My suggestion, drag your fat ass to a starbucks and shuffle up and deal. But go ahead and eat the pringles anyway. Pringles are awesome.