ORA-01810: format code appears twice tips Oracle Error Tips by Donald Burleson(S. Karam)

 

The Oracle docs note this on the ORA-01810 error:

 

NOTE: ORA-01810 does not exist on Oracle 10g per Oracle documentation

Oracle MOSC documents show that ORA-01810 is associated with a bug which has no current workarounds, although the following versions have been fixed:

8.1.7.3 (Server Patch Set)
9.0.1.3 (Server Patch Set)
9.2.0.1 (Base Release)

Also on the MOSC was a problem with ORA-01810 in which a user was seeing ORA-01810 when they attempted to connect with SQL*PLUS version. 

The issue was resolved by an Oracle reply:

This is genrally because the client and server date formats are different.
Client is sending data in RRRR format while the database is expecting
only RR format.
1.Modify the NLS_DATE parameter in the registry.
2.Start the registry editor
Find the ORACLE key
3.HKEY_LOCAL_MACHINE > Software > ORACLE
4.Single click on it to populate the right-hand window
In the right-hand window, look for the value NLS_DATE (or NLS_DATE_FORMAT) and double click on it.
5. Change the value to read DD-MON-RR

If the value is not present add it by selecting Edit > New > key
Add the key with the above information.