Oracle Client: 32 vs 64 bit
You should be aware that 32bit applications can not use the 64bit Oracle Client installation.
For now, all TD build applications (TD 1.x up to TD 6.2) on Win32 platform are 32bit.
Only on the .NET platform, starting with TD 6.2, you are able to build 64bit .NET targets.
So rule is, always use 32bit Oracle Client installations when building Win32 TD applications.
When building TD 6.2 .NET targets on 64bit, you can use the Oracle 64bit Client.