Hi,
It sounds Like there is a conflict between the oracle clients installed or tnsnames is not configured properly.
First set the ORACLE_HOME env variable and point it to oracle 64bit folder then add the ORACLE 64 bit bin directory path to PATH env variable and if you want you can also add TNS_ADMIN variable to point to ou tnsnames.ora path.
Then on the ORACLE bin 64 and run the tnsping to ping your SID. Do you get any errors this stage. If not continue with your Ds Srepo creation/testing.
Let me know if this helps.
Thanks