Access VBA not appending date properly in loop - vba

Question

I'm trying to make a loop that (among other things) inserts a date and then in each row, adds a month to that date. It is not appending the first date properly. The date is a DLookup from a date field in a query, so I think it should work as a date. And I don't see anything wrong with my SQL statement. But when this runs the date shows up in the table as 12/30/1899 and if you click on it, it changes to 12:03:34 AM. It's supposed to be 5/1/15. Nothing I've tried to get this to work has given me any other results.
Here's my code, please note: there's probably a couple other things wrong with my overall code I'm sure, but I'm focusing on this date problem for now. Feel free to point out whatever you find, though.
Private Sub AmortButton_Click()
DoCmd.SetWarnings False
Dim Account As Long: Account = DLookup("[L#]", "qry_info4amort") 'working
Dim StartDate As Date: StartDate = CDate(DLookup("PaidToDate", "qry_info4amort")) 'NOT WORKING
Dim InterestRate As Double: InterestRate = DLookup("IntCur", "qry_info4amort") 'working
Dim piConstant As Integer: piConstant = DLookup("[P&IConstant]", "qry_info4amort")
Dim UPB As Currency: UPB = DLookup("UPB", "qry_info4amort") 'working
Dim tempUPB As Currency: tempUPB = UPB 'working (just to establish variable)
Dim AmortInterest As Currency: AmortInterest = 0 'working (just to establish variable)
Dim AmortPrincipal As Currency: AmortPrincipal = 0 'working (just to establish variable)
Dim Ranking As Integer: Ranking = 1 'working (just to establish variable)
Dim PaymentLoop As Integer: PaymentLoop = 1 'working (just to establish variable)
Dim PaymentNumber As Integer: PaymentNumber = DLookup("NumPmts", "qry_info4amort") 'working
Dim tempInterest As Integer: tempInterest = 0 'working (just to establish variable)
Do While PaymentLoop <= PaymentNumber 'working
tempInterest = Round(tempUPB * (InterestRate / 12), 2)
tempUPB = Round(tempUPB - (piConstant - tempInterest), 2)
AmortPrincipal = AmortPrincipal + (piConstant - tempInterest)
AmortPrincipal = (piConstant - tempInterest)
AmortInterest = AmortInterest + tempInterest
DoCmd.RunSQL "INSERT INTO tbl_AmortizationTest ([L#],[Payment#],[PaymentDate],[UPB],[Interest],[Principal],[TotalPayment],[InterestRate],[TempUPB],[Ranking]) " & _
"VALUES (" & Account & "," & PaymentLoop & "," & StartDate & "," & UPB & "," & tempInterest & "," & AmortPrincipal & "," & (tempInterest + AmortPrincipal) & "," & InterestRate & "," & tempUPB & "," & Ranking & ")"
UPB = tempUPB
StartDate = DateAdd("m", 1, StartDate) 'NOT WORKING
PaymentLoop = PaymentLoop + 1 'working
Ranking = Ranking + 1 'working
Loop
MsgBox "Done!"
DoCmd.SetWarnings True
End Sub

Answer 1

First, if PaidToDate is of data type Date, retrieve your date as is:
StartDate = DLookup("PaidToDate", "qry_info4amort")
If it is a string, CDate or DateValue will do:
StartDate = DateValue(DLookup("PaidToDate", "qry_info4amort"))
Second, format a proper string expression for the date when concatenating it into SQL:
... PaymentLoop & ",#" & Format(StartDate, "yyyy\/mm\/dd") & "#," & UPB ...

Answer 2

Instead of using CDate() around your DLookup("PaidToDate", "qry_info4amort") you are probably going to have to pull out the relevant parts piece by piece...
StartDate = DateSerial(<year>, <month>, <day>)
For example, if DLookup("PaidToDate", "qry_info4amort") returns 05012015 then you could do:
StartDate = DateSerial(Mid(DLookup("PaidToDate", "qry_info4amort"),5,4), Left(DLookup("PaidToDate", "qry_info4amort"),2), Mid(DLookup("PaidToDate", "qry_info4amort"),3,2))
If the DLookup("PaidToDate", "qry_info4amort") returns a value with / in it, then you will have to use some Instr() functions... More on that here.