Typically, the platform is Linux and the database is on a seperate server, but there is a potential that it can happen with other configurations.
If this is a single-tiered environment, the ORACLE_HOME is where the Oracle RDBMS has been installed, typically: /opt/oracle/product/10.2.0/db_1
In a multi-tiered environment, where the update is being executed on a server apart from the Database server, the ORACLE_HOME is where the Oracle client has been installed, typically: /opt/oracle/product/10.2.0/client or /opt/oracle/product/10.2.0
To change permissions, log into linux as root and do the following:> chmod 755 -R /opt/oracle/product/10.2.0/
Test by logging into linux as the account that "owns" Vontu and try creating a file in the Oracle home directory.