Please let us know which note i should follow now. And in the note "1500361.1" which you gave is having below solution .
Please make the IFILE /orabase/asg/product/db/10.2.0/network/admin/ASGPERF_ap****/sqlnet_ifile.ora into a blank file.*
Then try to start the listener.
The listener should now start. Also when Autoconfig is next run, the IFILE which is not built through Autoconfig should not be reconfigured, it should remain blank and therefore running Autoconfig would not affect a change.
Here my doubt is what is IFILE, Please let us know which file i should make blank.
The listener service is already up in DB.