can't use linuxmint as hotspot

[northcamel]

Before I turn to linux mint, I use ubuntu12.04 well and I can easily set up wireless sharing using network manager.
But in linux mint, I configure as the same as in ubuntu12.04, my smartphone can only connect the established hotspot normally but it can't get access to the internet.
I confiure as the same as this viedo in Youtube (http://www.youtube.com/watch?v=Kqu93BhSAxw) . I don't know what's wrong.
Anyone who have the experience of setting up hotspot please help me.
Thanks in anvance!
Excuse for my poor English.

[farvardin]

I tried the same (I don't have a wifi gateway, only a wired ethernet connection), with a wifi usb key (dml-g122 rev C). While I can configure the wifi key as an ad-hoc connection, and on my smartphone connect to it (I'm close to the key so the signal is excellent), the smartphone after a while search for an IP, and when it's connected, the key then closes the connection. I could connect with the same key on windows with an utility called "connectivity" or something like that.

[opensam]

i saw the same video and it worked for lm11 but not for lm13 cinnamon