Hi Amal,
i just went throught the guide and they use /oracle/DBSID/102_64 as an example,
Home directory for Oracle instance
/oracle/<DBSID>/<102_32 or 102_64>
the solution to this tread was to re-install oracle (http://sap.ittoolbox.com/groups/technical-functional/sap-basis/dbhome-has-to-be-a-valid-oracle_home-1360307)
but you can as a test just create synbolic link and retry and if it works
ln -s /oracle/product/10.2/db_1 /oracle/DBSID/102_64
Best Regards
Marius