11gR2 : How to stop audit/trace files generation when importing data ?

 Hi ,

I would like to know , how to stop audit and trace generation in 11g database when trying to do un IMPORT with oracle imp utility.

/app/oracle/oradiag/diag/.../trace/*.trm

/app/oracle/oradiag/diag/.../trace/*.trc

/app/oracle/oradiag/diag/.../trace/trace/metadata/*.ams

/app/oracle/oradiag/diag/.../trace/trace/lck/*.lck

I have tried NOAUDIT ALL;

and these actions :

alter system set audit_trail=NONE scope=spfile;

alter system set trace_enabled=FALSE scope=both;

alter system set audit_sys_operations=FALSE scope=both;

but problem still remains  and SYS.AUD$ grows ... when importing data threfore import fails because no space available ...