Converting wireless card into wireless access pointer

Hi,

I am trying to share my Ethernet connected Internet via wireless LAN. I am on Ubuntu 10.04.

I tried to create a wireless network by Network Manager's "create new wireless network" Option. I used wireless mode as ad-hoc and IPv4 setting's method as "Shared to other computers". I tried using every encryption to setup the wlan. Only "WPA & WPA2 Personal" security setting setup the WLAN successfully. but I can't connect to that wlan and it seems as disabled in the network manger applet(in dark font).

What am i missing here?

Is there any mode or any kernel module need to enable or some other problem?

Please help me.

Thank you