HI ggnanaraj,
I'm working on the same server and able to connect internal and able to do all my normal activities. Only when I try to connect to some other user like sys, system or anyother, i face ...
ORA-12500 TNS: listener failed to start a dedicated shared server proces.
I have tried everything you told like processes parameter, deleteing .dat file for disabling OTRACE etc. Still same problem buddy...
Any idea??