ERwin DM: what are the basic steps to diagnose when I am trying to connect to Oracle and I get th (4307529)

basic steps to diagnose when I am trying to connect to Oracle and I get the error: ORA-01041: internal error, hostdef extension doesn't exist'?

Description:
What are the basic steps to diagnose when I am trying to connect to Oracle and I get the error: ORA-01041: internal error, hostdef extension doesn't exist'?

Solution:

That message means the pointer to hostdef extension in hostdef is null.  Here are some points that may help you to overcome that condition:

1. Check if the Oracle Server is powered down or if the listener service has been turned off or disabled on the server.
2. Use fully qualified names in your tnsnames.ora file.
3. Make sure that the Oracle character set settings on your client PC matches the Oracle character set settings on the server.
4. Check if more than one copy of OCIW32.DLL resides on the PC. If so, rename the other copies you are not using (if they are older or mismatch with the current Oracle client/server version).
5. If you have multiple instances of Oracle (like 10g and 11g) make sure your path statement is pointing to the correct version.
6. Check Oracle's ALERT.LOG file for any errors.

NOTE: The Oracle DLL required by ERwin to connect to Oracle dbms is either oci.dll or ociw32.dll. So having the presence of one of those two DLLs in the path on the client machine should allow ERwin to connect to Oracle dbms.