ORA-49100: Failed to process event statement […]

SQL> alter session set events 'sql_trace [sql:8x615vyks733p] wait=false, bind=false, planstat=never';
ORA-49100: Failed to process event statement [sql_trace [sql:8x615vyks733p] wait=false, bind=false, planstat=never] 
ORA-49104: [PLANSTAT] is not a valid argument for event [sql_trace]

SQL> alter session set events='1348 trace name errorstack, level 12, lifetime 1';
ORA-49100: Failed to process event statement [1348 trace name errorstack, level 12, lifetime 1] 
ORA-49601: syntax error: found ",": expecting one of: "End-of-Statement" etc..