Missing or invalid version of SQL library PSORA64 (200, 0) error with PT8.54

Error Message: Missing or invalid version of SQL library PSORA64 (200, 0)
I received this error while trying to open the application designer for PeopleTools 8.54.

Root Cause: 
By now you would have come across the news that PT8.54 is a 64 bit application. Like me, if you forgot to install the Oracle 64 bit client and tried to access PT8.54 with the existing 32 bit Oracle client you will receive this particular error message. 

Remedy:
Download the Oracle 64 bit client from Oracle site (link here) and install it. Once installed you should not get this error anymore. Do not forget to update the tnsnames.ora file for the 64 bit client.

If you still receive the error, check the PATH environment variable value of your PC. Very unlikely, but it could be possible that the ORA_HOME of the 64 bit client was somehow not appended to the PATH value during the installation. You can manually add it to resolve the issue.

Note: Although Oracle 12c 64 bit client which is the latest version available I could not install it (Installation was stuck at the skip update step despite trying several things). So I ended up choosing the older version i.e 11gR2 client which worked without any hitch.