Calendar control's value property acting strange

[Jables]

I have a form with the Microsoft Calendar Control 7.0 on it. There is a subform that gets filtered by the date selected on the calendar. When the form loads, the following happens:

Me.axCal.Value = FormatDateTime(Now(), vbShortDate)
'Code debugs to the line below
Me.frmtime_subform.Form.Filter = "[Date Worked] = #" & _
                                 Me.axCal.Value & "#"
Me.frmtime_subform.Form.OrderBy = "[Date Worked],[Started]"
Me.frmtime_subform.Form.FilterOn = True
Me.frmtime_subform.Form.OrderByOn = True

This code works fine, but here's where it gets weird. Every third time I open the form, I get an error that debugs to the commented line above. The error is:

Err.Number: 2455
Err.Descriptoin: You entered an expression that has an invalid reference to the property. The property may not exist or may not apply to the object you specified.

Even stranger is that when I say every third time, I mean that error pops up when doing the following:

1) open the form twice
2) get the error on the third time the form is opened
3) close the form
4) open it once more
5) CLOSE ACCESS
6) open the application again
7) open the form once more with no errors
8) close it again
9) open it the third time, AND THE ERROR APPEARS AGAIN.

So the pattern seems to carry through even after Access is completely shut down and open again. I'm stuck. Any help would be greatly appreciated.