Computer Internet Connectivity Error wit...

Chinese Mobile CECT V180
Installed MTK GPRS USB Modem on Computer connected via Data Cable as Com Port
Connected successfully
After Dialing *99***1# via spice Network for internet,
Username and Password is verified Succesfully....while Registering your computer over Network ...
G(GPRS Status) appears on mobile and suddenly get disappear.
.and computer gives Error No 734.....
I have cleared LCP Connections.
Spice Network working Succsfully checked with other Cellphone via Nokia IRDA Modem
also GPRS Connects and works well on Mobile
Please Help Me