I have Nokia 5230 mobile phone and using it with the Airtel sim card. Yesterday when i made a topup of 98 rs. for having the gprs plan of 2GB free browsing for a month. It was done correctly and the plan was activated. After that when i tried to open any web page i got an error message that "no packet data available", i tried for several time and reset the gprs setting on the phone. But after some time i got an error message stating that "sim card registration failed", i don't know what is going on. Please help me..