SP2-0735 is a SQL*Plus error which is very much like SP2-0158, they alert users that SQL*Plus cannot recognize the issued command. For example:
SQL> set statementcache 15;
SP2-0735: unknown SET option beginning "statementc..."
This is because SET STATEMENTCACHE command is a new feature of SQL*Plus 12.2, so you will see SP2-0735 if you're using SQL*Plus before release 12.2.
The solution is simple, find out the supported release of SQL*Plus and use it to do your job, which is usually a higher release of SQL*Plus.