I'm a bit late for this, but if someone arrives here looking for this question, here is the answer. It worked for me in Ubuntu 11.04 and 11.10.
Open a terminal and type
sudo modprobe -r acer_wmi
You should be able to connect to the wireless till next reboot.
- Making the change permanent
Edit the file
/etc/modprobe.d/blacklist.conf with your favorite text editor, ie
gksu gedit /etc/modprobe.d/blacklist.conf, and add this line at the end of the file
Reboot and you’re done.
Please note: This applies to wireless card having rtl8188ce chipset. You can view that by typing
lspci in a terminal and searching for the entries respective to Network Controller.
The problem should be solved for Ubuntu 12.04.