13Type Mismatch Access 2007 - vba

Question

I'm attempting to fix some botched up VBA from someone whom I inherited this Access database from. Aside from the hardly-useful notes left in VBA, there is no documentation, so I am trying to figure out what everything does, and if it is correct. I continue getting a 13Type Mismatch error when I am Clicking a button to add either units or a value to a table of Contributions. I thought it was an easy fix such as a messed up variable declaration, however I've changed them to Double and it didn't seem to correct my error. Does anyone see anything off the bat that they might recognize as throwing this error? Thanks ahead of time for your efforts.
Private Sub AddContributionBtn_Click()
On Error GoTo Err_AddContributionBtn
Dim Cancel As Integer
Dim CurrentNAVDate As Date
Dim CurrentNAV As Double
Dim ConfirmAddCont As Double
Dim CalcContUnits As Double
Dim CalcContValue As Double
Dim StringSQL As String
'get current NAV
CurrentNAVDate = Format(DateAdd("s", -1, DateAdd("q", DateDiff("q", "1/1/1900", Date), "1/1/1900")), "Short Date")
CurrentNAV = Format(DLookup("NetAssetValue", "NAV_Tbl", "Format(NAV_Date, ""mmddyyyy"") = " & Format(CurrentNAVDate, "mmddyyyy")), "Currency")
'validation to require either contribution units or value is entered, not both
If IsNull(Me.ContValueTxt) = True And IsNull(Me.ContUnitsTxt) = True Then
MsgBox "Please enter contribution units or value."
Me.ContUnitsTxt.SetFocus
Cancel = True
Exit Sub
ElseIf IsNull(Me.ContValueTxt) = False And IsNull(Me.ContUnitsTxt) = False Then
MsgBox "Both contribution units and value may not be entered."
Me.ContUnitsTxt.SetFocus
Cancel = True
Exit Sub
Else:
If IsNull(Me.ContValueTxt) = True And IsNull(Me.ContUnitsTxt) = False Then
'calculate contribution value from units
CalcContUnits = Me.ContUnitsTxt
CalcContValue = CalcContUnits * CurrentNAV
GoTo ConfirmAppend
ElseIf IsNull(Me.ContValueTxt) = False And IsNull(Me.ContUnitsTxt) = True Then
'calculate contribution units from value
CalcContValue = Me.ContValueTxt
CalcContUnits = CalcContValue / CurrentNAV
GoTo ConfirmAppend
End If
End If
ConfirmAppend:
'confirm contribution value and units, run append query
ConfirmAddCont = MsgBox("Add " & Format(CalcContUnits, "fixed") & " units for a contribution value of " & Format(CalcContValue, "currency") & "?", _
vbOKCancel, "Add Contribution")
If ConfirmAddCont = vbOK Then
DoCmd.Hourglass True
DoCmd.SetWarnings False
StringSQL = "INSERT INTO ContributionTbl(ContDate, ContUnits, ContNAV, ContType) VALUES (#" & Date & "#, " & CalcContUnits & ", #" & CurrentNAVDate & "#, " & 1 & ");"
DoCmd.RunSQL (StringSQL)
DoCmd.SetWarnings True
DoCmd.Hourglass False
Me.ContUnitsTxt = Null
Me.ContValueTxt = Null
Forms!PlanFrm![PlanContributedUnitsFrm].Requery
Else
Cancel = True
Exit Sub
End If
Exit_AddContributionBtn:
Exit Sub
Err_AddContributionBtn:
MsgBox Err.Number & Err.Description
Resume Exit_AddContributionBtn
End Sub

Answer 1

As shown in the discussion, I make our guess clearer in this temporary reponse:
Error may be here:
CurrentNAV = Format(DLookup("NetAssetValue", "NAV_Tbl", "Format(NAV_Date, ""mmddyyyy"") = " & Format(CurrentNAVDate, "mmddyyyy")), "Currency")
as DLookup("NetAssetValue",...) gets NULL,
Format(NULL, "Currency") gets 13 Type Mismatch, as I've reproduced this in Access 2007.
This can be explained:
Since there is no recent date in the table field NAV_Tbl.NetAssetValue, as in the case we get the date CurrentNAVDate = 09/30/2013 (last date of the last quarter).
So you may try code like this, by introducing varCurrency variable to handle this NULL value case:
Private Sub AddContributionBtn_Click()
On Error GoTo Err_AddContributionBtn
Dim Cancel As Integer
Dim CurrentNAVDate As Date
Dim CurrentNAV As Double
Dim ConfirmAddCont As Double
Dim CalcContUnits As Double
Dim CalcContValue As Double
Dim StringSQL As String
Dim varCurrency
'get current NAV
CurrentNAVDate = Format(DateAdd("s", -1, DateAdd("q", DateDiff("q", "1/1/1900", Date), "1/1/1900")), "Short Date")
varCurrency = DLookup("NetAssetValue", "NAV_Tbl", "Format(NAV_Date, ""mmddyyyy"") = " & Format(CurrentNAVDate, "mmddyyyy"))
If(IsNull(varCurrency) then
CurrentNAV = 0
Else
CurrentNAV = Format(varCurrency, "Currency")
End If
'validation to require either contribution units or value is entered, not both
If IsNull(Me.ContValueTxt) = True And IsNull(Me.ContUnitsTxt) = True Then
MsgBox "Please enter contribution units or value."
Me.ContUnitsTxt.SetFocus
Cancel = True
Exit Sub
ElseIf IsNull(Me.ContValueTxt) = False And IsNull(Me.ContUnitsTxt) = False Then
MsgBox "Both contribution units and value may not be entered."
Me.ContUnitsTxt.SetFocus
Cancel = True
Exit Sub
Else:
If IsNull(Me.ContValueTxt) = True And IsNull(Me.ContUnitsTxt) = False Then
'calculate contribution value from units
CalcContUnits = Me.ContUnitsTxt
CalcContValue = CalcContUnits * CurrentNAV
GoTo ConfirmAppend
ElseIf IsNull(Me.ContValueTxt) = False And IsNull(Me.ContUnitsTxt) = True Then
'calculate contribution units from value
CalcContValue = Me.ContValueTxt
CalcContUnits = CalcContValue / CurrentNAV
GoTo ConfirmAppend
End If
End If
ConfirmAppend:
'confirm contribution value and units, run append query
ConfirmAddCont = MsgBox("Add " & Format(CalcContUnits, "fixed") & " units for a contribution value of " & Format(CalcContValue, "currency") & "?", _
vbOKCancel, "Add Contribution")
If ConfirmAddCont = vbOK Then
DoCmd.Hourglass True
DoCmd.SetWarnings False
StringSQL = "INSERT INTO ContributionTbl(ContDate, ContUnits, ContNAV, ContType) VALUES (#" & Date & "#, " & CalcContUnits & ", #" & CurrentNAVDate & "#, " & 1 & ");"
DoCmd.RunSQL (StringSQL)
DoCmd.SetWarnings True
DoCmd.Hourglass False
Me.ContUnitsTxt = Null
Me.ContValueTxt = Null
Forms!PlanFrm![PlanContributedUnitsFrm].Requery
Else
Cancel = True
Exit Sub
End If
Exit_AddContributionBtn:
Exit Sub
Err_AddContributionBtn:
MsgBox Err.Number & Err.Description
Resume Exit_AddContributionBtn
End Sub
For DLookup():
varCurrency = DLookup("NetAssetValue", "NAV_Tbl", "NAV_Date >= #" & Format(CurrentNAVDate, "yyyy-mm-dd") & "#")