Ubuntu – RTL8188RU usb wireless card issue

I bought a usb wireless card with RTL8188RU chipset.
And I use it with Ubuntu 12.04.3.
But it only can scan SSIDs. The connection is always failed.

Then I found that build-in driver rtl8192cu is buggy from google.
So I install official Realtek driver 4.0.2_9000 successfully.
Also add rtl8192cu to blacklist and add 8192cu to /etc/modules

But the problem is still the same.
There are some errors in dmesg.

[32174.031125] link to new AP
[32174.328532] link_timer_hdl: auth timeout and try again
[32174.631246] link_timer_hdl: auth timeout and try again
[32174.934012] link_timer_hdl: auth timeout and try again
[32175.236757] link_timer_hdl: auth timeout and try again
[32175.539467] report_join_res(-1)

These errors shows even the wifi is open without password.

Information from lsusb.

Bus 001 Device 003: ID 0bda:817f Realtek Semiconductor Corp.

Anyone could help? Thanks