The customer is using Firefox, 3.5 in this case, and Internet Explorer (6!). Suddenly the application does not work anymore for a lot of clients, as a matter of fact, the firefox-users. They had upgraded their Firefox to 3.6., and got the message that an add-on must me installed ( appears to be the JRE ) . After installing this, it still does not work.
After "alter table DWHINCIDENT.TEST_TABLE drop unused columns checkpoint 100000" And after a while: ERROR at line 1: ORA-00600: internal error code, arguments: , [0x12CB1C820], , , , Table in usable state. New bug !