preparing sql with datetime using 7.30.UC1

Hello all, I have noticed that a string prepare that works on other 4gl versions running on HP-UX does not work on version 7.30.UC1 running on AIX, even though it will run quite happily in isql in the same instance. eg preparing "SELECT EXTEND( aassg.start_dtim, HOUR TO SECOND ) - ", "DATETIME(00:00) HOUR TO MINUTE start ", " from aassg " gives a syntax error -201, but preparing "SELECT EXTEND( aassg.start_dtim, HOUR TO SECOND ) - ", "DATETIME(00) HOUR TO HOUR start ", " from aassg " works ok. This is not really giving me any trouble at the moment, but I am curious as to why this should suddenly not work. Is this a bug in that version, or am I doing something wrong? Thanks, Sue