Hello Hemakumar,
the init state is theone of the first states in OSPF neighbor state machine.
This state specifies that the router has received a hello packet from its neighbor, but the receiving router's ID was not included in the hello packet. When a router receives a hello packet from a neighbor, it should list the sender's router ID in its hello packet as an acknowledgment that it received a valid hello packet.
see
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093f0e.shtml#init
Regressing to INIT state means the local node does not see its own Router-id listed in the neighbor originated Hello.
If you can access the neighbor device you should check that router log to see if the interface has flapped and what kind of OSPF neighbor change has happened.
For troubleshooting problems in OSPF adjacency formation you can use
debug ip ospf adj
It should provide enough information to understand what is going wrong.
Hope to help
Giuseppe
