I Installed Oracle 12C forms.
When I try to run FRMBLD,I get the following error:
FRM-18122:Oracle Forms Debugger failed to initialize.
I click on Ok.
Under the Data Block Wizard when trying to connect, I get the following error:

ORA-12154: TNS:could not resolve the connect identifer specified.

I am enclosing a copy of the tnsnames.ora, sqlnet.ora and listiner.ora file with the results of the listener file.

The TNSNAMES.ORA is in the proper directory.
All the syntax looks correct and there is no unmatched parentheses or stray characters.
I am not using LPAD or EZCONNECT.
I added the pdborcl to the TNSNAMES.ORA file.
I put the TNSNAMES.ORA IN THE FORMS HOME and changed the path in the Environmant Variables file under the System variables group
with the same results.

Here is my tnsping alias and the listener status:

C:\Users\Windows 7>tnsping orcl

TNS Ping Utility for 64-bit Windows: Version 12.1.0.2.0 - Production on 18-MAR-2019 09:05:56

Copyright (c) 1997, 2014, Oracle. All rights reserved.

Used parameter files:
C:\ORACLE_12C_DATABASE\product\12.1.0\dbhome_1\network\admin\sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = orcl)))
OK (40 msec)

C:\Users\Windows 7>lsnrctl status

LSNRCTL for 64-bit Windows: Version 12.1.0.2.0 - Production on 18-MAR-2019 09:06:30

Copyright (c) 1991, 2014, Oracle. All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)(HOST=localhost)(PORT=1521)))
STATUS of the LISTENER
------------------------
Alias LISTENER
Version TNSLSNR for 64-bit Windows: Version 12.1.0.2.0 - Production
Start Date 16-MAR-2019 13:24:41
Uptime 1 days 19 hr. 41 min. 49 sec
Trace Level off
Security ON: Local OS Authentication
SNMP OFF
Listener Parameter File C:\ORACLE_12C_DATABASE\product\12.1.0\dbhome_1\network\admin\listener.ora
Listener Log File C:\ORACLE_12C_DATABASE\diag\tnslsnr\Window10PRO\listener\alert\log.xml
Listening Endpoints Summary...
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)(HOST=127.0.0.1)(PORT=1521)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=ipc)(PIPENAME=\\.\pipe\EXTPROC1521ipc)))
(DESCRIPTION=(ADDRESS=(PROTOCOL=tcps)(HOST=Window10PRO)(PORT=5500))(Security=(my_wallet_directory=C:\ORACLE_12C_DATABASE\admin\orcl\x db_wallet))(Presentation=HTTP)(Session=RAW))
Services Summary...
Service "CLRExtProc" has 1 instance(s).
Instance "CLRExtProc", status UNKNOWN, has 1 handler(s) for this service...
Service "orcl" has 1 instance(s).
Instance "orcl", status READY, has 1 handler(s) for this service...
Service "orclXDB" has 1 instance(s).
Instance "orcl", status READY, has 1 handler(s) for this service...
Service "pdborcl" has 1 instance(s).
Instance "orcl", status READY, has 1 handler(s) for this service...
The command completed successfully

Here is my tnsping alias and the listener status:

I added pbdorcl to the tnsnames.ora file in the forms directory:

pdbORCL =
(DESCRIPTION =
(ADDRESS = (PROTOCOL = TCP)(HOST = localhost)(PORT = 1521))
(CONNECT_DATA =
(SERVER = DEDICATED)
(SERVICE_NAME = pdborcl)
))

Really?
host points to where the DB host is. If it's on the same machine as the client then what would you put in client tnsnames other than localhost?

I had the variable set to C:\ORACLE_12C_DATABASE\PRODUCT\12.1.0\DBHOME_1\NETWORK\ADMIN

I had the variable set to C:\ORACLE_12C_DATABASE\PRODUCT\12.1.0\DBHOME_1\NETWORK\ADMIN

Wideminnow6970 wrote on Thu, 21 March 2019 16:26

I had the variable set to C:\ORACLE_12C_DATABASE\PRODUCT\12.1.0\DBHOME_1\NETWORK\ADMIN

That's nice.

Please realize & understand that FORMS has it own ORACLE_HOME tree & uses the tnsnames.ora file from under it.

So I am not surprised that the error for FORMS still occurs when you have NOT corrected the underlying problem.

Oracle error message & code is how it informs you that a problem exists.

I had the variable set to C:\ORACLE_12C_DATABASE\PRODUCT\12.1.0\DBHOME_1\NETWORK\ADMIN

Wideminnow6970 wrote on Thu, 21 March 2019 23:26

I had the variable set to C:\ORACLE_12C_DATABASE\PRODUCT\12.1.0\DBHOME_1\NETWORK\ADMIN

I'll try again. You have to provide complete information. In this case, where did you set this variable? It would need to be in the registry, so that all shells can pick it up.
You have not shown a tnsping of pdbrcl.
You have not shown how you have configured Forms to use pdborcl.

The variables were set in the Environment Variable screen:
tns_admin = C:\ORACLE\product\12.1.0\dbhome_1\NETWORK\ADMIN\TNSNAMES.ORA
forms_Path = C:\ORACLE\Middleware\Oracle_Home\forms\java\frmall.jar;C:\ORACLE\Middleware\Oracle_Home\forms\java\FRMWEBUTIL.JAR
forms_builder_classpath = c:\ORACLE\Middleware\Oracle_Home\bin\frmbld.exe;C:\ORACLE\Middleware\Oracle_Home\forms\templates\config\DEFAULT.ENV

Here is the tnsping of pdbrcl:
C:\Users\Windows 7>TNSPING PDBRCL

TNS Ping Utility for 64-bit Windows: Version 12.1.0.2.0 - Production on 01-MAY-2019 15:27:40

Copyright (c) 1997, 2014, Oracle. All rights reserved.
Used parameter files:
C:\ORACLE\product\12.1.0\dbhome_1\network\admin\sqlnet.ora

TNS-03505: Failed to resolve name

Hopefully this is all that you need