In Addition to my Previous reply.... I've sorted out the No circuit channel available issue.....

I've blackberry 9550 os 5.0 1015 .... installed on the device.... i was facing the issue on tata docomo network...

i downgraded the os to 5.0 713 the problem got resolved automatically. I think their is the issue of mismatch of Band selection on handset and from network side...

The operator doesn't support the band on which BB handset operate.

Kindly do the downgrade and tell me the success story..
regards..
Vikram