Exec Proc Based on DateTime Fields

[Hexonx]

I'm executing a stored procedure that filters on datetime input parms. This is the procedure:

Input parms: @ai_d_startdate (datetime), @ai_d_enddate (datetime)

-- If no end time, default to 1-hour block of time
if @ai_d_enddate is null
	select @ai_d_enddate = DATEADD(hh, 1, @ai_d_startdate)


-- Convert input parms to compatible format
select @ai_d_startdate = convert(datetime, @ai_d_startdate, 110) --101)
select @ai_d_enddate = convert(datetime, @ai_d_enddate, 110) --101)


-- Constant for Therapist provider type/category
declare @PROVIDER_TYPE_THERAPIST int
select @PROVIDER_TYPE_THERAPIST = 2
 
Select  s.VisitDateTime, s.PatientSchedID,
		s.ServiceID,
		p.Firstname + ' ' + p.lastname 'PatientName', 
		s.VisitReason, 
		r.firstname + ' ' + r.lastname 'TherapistName'
From    Patient p,
		Patient_schedule s,
		provider r
Where   p.patientId = s.patientId and
		r.providerId = s.providerId and
		r.ProviderTypeID = @PROVIDER_TYPE_THERAPIST and
		s.VisitDateTime between @ai_d_startdate and @ai_d_enddate

When I run from CAST SQL Builder (a query analyzer) I get the result set I expect, but when I execute via ADO 2.5, I get an opened Recordset with no records.

I tried setting Parameter types to adDate and adDBDate, but no effect.

The value that the Parameter object is sending to the DB is #1/27/1997 8:00:00 AM#.

No errors are generated on execution.

Any ideas?