We are getting error in schema creation while installing windchill 10.2

Could you attach PSI log from Windchill 10.2/PSI/installer/logs?

Work around is to create the schema first run using PSI, then run it again to install the rest of the solution. 

If that doesn't work either, you can also create schema using commandline. 

Check your Oracle version.

Set SQLNET.AUTHENTICATION_SERVICES to NONE in the sqlnet.ora client file