SQL Trigger (Oracle)
===

I'm new to SQL and I'm trying to create a trigger that would insert into an audit table. 

    create or replace trigger late_ship_insert
    after insert on suborder
    for each row
    declare
    employee int;
    begin
    select emp_id into employee
    from handles
    where order_no = :new.order_no;
    if :new.actual_ship_date > :new.req_ship_date then
    insert into ship_audit
    values (employee, :new.order_no, :new.suborder_no, :new.req_ship_date, :new.actual_ship_date);
    end;

Error:

    Warning: execution completed with warning
    trigger late_ship_insert Compiled.

But once I try an insert statement it tell me the trigger is not working it to drop it.

    Error starting at line 1 in command:
    insert into suborder 
    	values	( 8, 3, '10-jun-2012', '12-jul-2012', 'CVS', 3) 
    Error at Command Line:1 Column:12
    Error report:
    SQL Error: ORA-04098: trigger 'COMPANY.LATE_SHIP_INSERT' is invalid and failed re-validation
    04098. 00000 -  "trigger '%s.%s' is invalid and failed re-validation"
    *Cause:    A trigger was attempted to be retrieved for execution and was
               found to be invalid.  This also means that compilation/authorization
               failed for the trigger.
    *Action:   Options are to resolve the compilation/authorization errors,
               disable the trigger, or drop the trigger.

Any idea what is causing this, any help would be greatly appreciated. Thanks!