Was following this thread a while ago, and found the answer to your problem:

DM>     I had a look at this but I have the same problem (error DM>
323 invalid  semaphore handle). Using what function would I DM> asign a
semaphore for use by  this call? (sorry I'm not DM> using "C"
and don't have the sample code you  mentioned DM> above).

Try this:

APIRET rc;
HTIMER Timer;
HEV SemHandle;
// Create event semaphore
rc=DosCreateEventSem((PSZ)NULL,&SemHandle,DC_SEM_SHARED,FALSE);if (rc!=0) {
     ThreadRC=1;
     _endthread();
};
// Set up timer to activate semaphore every 2 clock ticks
DosQuerySysInfo(QSV_TIMER_INTERVAL,QSV_TIMER_INTERVAL, &tms,
sizeof(tms));rc=DosStartTimer(tms*2/100,(HSEM)SemHandle,&Timer);
if (rc!=0) {
     DosCloseEventSem(SemHandle);
     ThreadRC=2;
     _endthread();
};

--- Maximus/2 3.01