The dynamic registration doesn't seem to work

The dynamic registration by PMON of the listener file doesn't seem to work.  I assume I should see something in listener.ora after awhile that points to my database?  I've tried bouncing the database, recreating the network files, and using the ALTER command which supposedly "forces" the registration to take place.  Nothing seems to happen.  Still getting TNS-03505 failed to resolve name, nothing new in the listener file.  Sometimes I also get 0ra-12541 TNS:no listener.  What am I missing.  Thanks!