Another use (dotcomboy) was having similar problem - here is his post:
I'm trying to setup a push replication from SQL 2005 to Oracle 10g and I'm getting errors. I've installed the complete 10g client along with OLEDB 10.2. I've granted complete rights to the oracle directory on the SQL server side. I can TNSPing the Oracle DB and I can connect to the DB via the Data Source (ODBC).
I've run out of ideas. Please HELP!
Here is my error from the replication monitor in SQL 2005.
The process could not connect to Subscriber 'TESTREP'. (Source: MSSQL_REPL, Error number: MSSQL_REPL20084)
Get help: http://help/MSSQL_REPL20084
ORA-12154: TNS:could not resolve the connect identifier specified (Source: MSSQL_REPL_ORACLE, Error number: 12154)
Get help: http://help/12154
If anyone is interested I figured it out.
it was simply copying over the tnsnames.ora from the original Oracle client install. After I installed the OLEDB it created a new oracle home and this is where sql was looking.
Hope this helps,