Not sure I understand the question.
604e is not power4.
Fron the 5.2 command reference is looks like -L was introduced at AIX 5.2:
http://publib16.boulder.ibm.com/pser...htm#a133z92594
-L Displays LPAR number and LPAR name. If LPAR does not exist, -1 is displayed for LPAR number and NULL for LPAR name.
So it seems your 604e machine might be running AIX 5.2 or 5.3 and of course a 604e won't support LPAR so you will get an output of -1 NULL.
Check the oslevel -r on the 604e and the power4 machines, IBM might have introduced the -L in a late ML of 5.1 but not documented it.
Come back with more information about the 604e and power4 systems and the oslevel output if you need more info.