I am not very sure, whether these help you.

1.)You must use the ROWS option with one in the command line because the records must be 
processed one at a time if you want 
to have the same sequence number in the two tables:

   sqlldr usr/pwd CONTROL=test.ctl ROWS=1

   are you doing that?
2.)
   This is a sample script from docs

   LOAD DATA 
   INFILE 'my_data.dat' 
   insert 
   INTO TABLE my_master 
   when (1:1) = 'M' 
   fields terminated by ',' optionally enclosed by '"' 
     (my_master_key position(1:2) "my_seq.nextval", 
      my_master_info 
     ) 
   into TABLE my_detail 
   when (1:1) = 'D' 
   fields terminated by ',' optionally enclosed by '"' 
     (my_detail_key position(1:2) "my_seq.currval", 
      my_detail_info 
     ) 

 
    In the control file you will see position(1:2) 
for BOTH MASTER AND DETAIL TABLES.  This tells  
Oracle that the INFO fields begin in position 3 
of each data line. 
are you doing this?