Alter table (no more locks)

HP-UX 10.20 IDS 7.30.UC2 I'm sure someone has run into this problem before. I locked a table in exclusive mode, then modified a column as: set lock mode to wait;begin work; lock table product in exclusive mode; alter table productmodify(category smallint); commit work; For which I received: Lockmode set. Started transaction. Table locked. 312: Cannot update system catalog (syscolauth). 134: ISAM error: no more locks Error in line 8Near character position 24 377: Must terminate transaction before closing database. 853: Current transaction has been rolled back due to erroror missing COMMIT WORK. I assume it must be running out of locks in a temp table, or the system table. How do I get around this? I could increase the number of locks, the table only has 120K or so rows. But suppose it had several million? Thanks in advance.