Forms :: Multi Values For One Single Record (student_id)

I am using forms 10g...

I have 2 blocks,in one i insert student_id and when i click on the button i should get all his courses in the other block...

BUT.. when the student has more than 1 course I get this:

when button pressed trigger raised unhandled exception ORA-01422

Here is the button

begin

select TEST_STUDENT_INFO.stud_name,TEST_STUD_CRSE_DETAIL.crse_no,
TEST_COURSES.crse_name,TEST_STUD_CRSE_DETAIL.crse_type,TEST_STUD_CRSE_DETAIL.crse_type_desc,
TEST_COURSES.crse_time
INTO :stud_name,:crse_no1,:crse_name,:crse_type1,:crse_type_desc1,:crse_time
from TEST_STUDENT_INFO,TEST_COURSES,TEST_STUD_CRSE_DETAIL
where (TEST_STUD_CRSE_DETAIL.STUD_ID =:TEST_STUD_CRSE_REG.STUD_ID)
and (TEST_STUDENT_INFO.STUD_ID =:TEST_STUD_CRSE_REG.STUD_ID)
and (TEST_COURSES.CRSE_NO = TEST_STUD_CRSE_DETAIL.CRSE_NO)
and (TEST_STUD_CRSE_DETAIL.CRSE_TYPE = TEST_COURSES.CRSE_TYPE);

end;

but if the student has ONLY ONE course it WORKS FINE!