A) Make sure that GPRS is connected and the icon appeared in status bar that indicates GPRS is available.
B) Make sure your phone has gained Root access permissions (Methods to gain Root access permissions are different for each brand and model, Please search the Internet for the method, you can refer to http://ask.zol.com.cn/t_7522/
C) Make sure that other non-OSCall WI-FI and GPRS function is turned off.
D) Make sure your SIM card has the internet function.
E) Make sure that the APN name is correct (APN name of SIM card belongs to China Mobile is cmnet, APN name of SIM card belongs to China Union is uniwap).
F) With Proxy Settings, make sure the Server and Port are correct (Please consult your operator for details).