sqlldr running slow after indexes created

let me explain this.... I had ran 1 session of sqlldr while I run indexes into a table for 6 fields... now the indexes are completed but the sqlldr running very slow it loads one file after each 30 minutes... now when I do any alterations to set the indexes off it won't let me do it and though an error of ( ORA-000054 and ORA-000604) even if I run another sqlldr.... any suggestion will be highly appreciated.... bellow is a sample of my control files header... OPTIONS(DIRECT=TRUE,ROWS=10000,BINDSIZE=209700000,readsize=209700000) load data append into table name FIELDS TERMINATED by '!' OPTIONALLY ENCLOSED by '"' trailing nullcols When I run the following query select * from dba_dml_locks session_id,owner,name,mode_held,mode_requested,last_convert,blocking_others 123,username,tablename,exclusive,none,1228,not blocking any suggestion ... this is my daily scheduler to load around 8000+ files around 20GB so any suggestion