I have a linked server created from SQL 2000. The oracle client is 9i. Some times the linked server gives error "Server: Msg 7399, Level 16, State 1, Line 1
OLE DB provider 'MSDAORA' reported an error.
[OLE/DB provider returned message: ORA-12545: Connect failed because target host or object does not exist
OLE DB error trace [OLE/DB Provider 'MSDAORA' IDBInitialize::Initialize returned 0x80004005: ]."

The TNSNAMES.ORA file is has the server IP address specified instead of name. Also sometimes the connection is successful and sometimes it failes with above error.

Can someone please help where the problem might be.