Type mismatch in Date/Time value build, starting 1-October.

[Enrique_]

This code has been working flawless for months of testing (of single digit month numbers?) until the calendar rolled over to 1-Oct or 10/1/2015.

Now its has a Type Mismatch error 13.

Here is the code:

Dim d0, d1, d2, d3 As Date
Dim drt as Date
'drt value loaded from database value, Format: Short Time, tested Medium Time, same prob.
'drt = 8:00
        d0 = DateAdd("d", -1, Date) ' Gets previous day's date
        d1 = Format(Now(), Date) ' Gets today's date
        'No error to this point
        '--- Error in below 2 lines ---
        d2 = d0 & " " & drt  'Combine previous day's date & DRT
        d3 = d1 & " " & drt  'Combine today's date & DRT

'Previous results looked like  d2 = 9/26/2015 8:00 AM, d3 = 9/27/2015 8:00 AM

When I was creating this I could display the newly created d2 and d3 and they were perfect, and worked in my SQL string.

I have tried everything I can think of.
What might have changed simply by the month change?

Any suggestions appreciated.