rdefmtdte() returns odd error code

We've just installed 5.0 on an Amdahl running UTS, and a piece of code that's been working fine for a couple of years under 4.0 is now giving us a strange error. For the following code: #include <sys/types.h> #include <time.h> CalTime(time_in, jdate, time_out) time_t *time_in; /* time value */ long *jdate; /* returned date */ char *time_out; /* returned time */ { int rslt; /* result field for rdefmtdate() */ char datestr[80]; /* buffer for function cftime */ [ some code that results in the string "Mar 10 1993" in array datestr ] rslt = rdefmtdate(jdate, "mmddyyyy", datestr); [ some code that checks rslt, and does more things with an intermediate date/time string ] } ...we get a return value of -1228 from rdefmtdate(). -1228 is not a documented return code for that subroutine, and the 5.0 error manual describes -1228 as a 4GL error having nothing whatsoever to do with dates. As stated in the above code fragment, we were verifiably getting the string "Mar 10 1993" in the datestr[] array. The 5.0 ESQL/C manual shows no change to the arguments passed to/from rdefmtdate(), and the code still runs OK on Suns running 4.0 and 5.0 and on two other UTS systems running 4.0. Anybody have any ideas? -Rich