OUI is unable to create or update the appropriate registry keys for 32-bit installation.
You can run the below query to make sure registry does not have the required key.
C:> reg query HKLM\SOFTWARE\WOW6432Node\ORACLE /v inst_loc ERROR: The system was unable to find the specified registry key or value.
Development team is currently working on this issue via bug 20219460
Monitor this Bug for the final solution, Bug 20219460 INSTALLER OUI DISAPPEARED ON INSTALLING WIN32 BIT CLIENT ON WINDOWS2012 R2 64BIT
1. Open registry
2. Go to HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node
3. Create a new key with name Oracle
4. Go to Oracle and then create a new String Value with name inst_loc
5. Give the value as C:\Program Files (x86)\Oracle\Inventory
6. Retry installation.
Source : oracle.com