Dlookup retrieves a date wrong - ms-access

Question

I'm trying to get a date in my database but when the day is less than 12, the month and the day are switched
Example: In the database 2012-02-10 (2 october 2012), the value I get when I do that:
lastDateMill = Nz(DLookup("LastContactDate", "Mills", "MillID = " & lstMills.Column(0, i)), 0)
is
lastDateMill = "10/02/2012"
So I thought that was only a format thing but when I do
Format(lastDateMill, "Long Date")
it equals "February-10-12"
This is how I update the date
DoCmd.RunSQL "UPDATE Mills SET LastContactDate = #" & SalesCallDate & "# WHERE MillID = " & lstMills.Column(0, i)
And the SalesCallDate = "2/10/2012" so the good date
So why the day and the month are switched?
The front end is ms-access-2010 and the back end is on SQL SERVER 2012

Answer 1

Your SalesCallDate variable contains a date as text:
SalesCallDate = "2/10/2012"
Apparently you intend the date format of that string to be m/d/yyyy, but it gets interpreted as d/m/yyyy format.
Store the string value in yyyy/mm/dd format to eliminate confusion due to locale issues ... 2012/02/10
Since it turns out that SalesCallDate is actually a text box containing a date value, change your UPDATE approach to avoid date problems due to locale.
Dim strUpdate As String
Dim db As DAO.Database
strUpdate = "UPDATE Mills SET LastContactDate = " & _
Format(Me.SalesCallDate, "\#yyyy-m-d\#") & vbCrLf & _
"WHERE MillID = " & Me.lstMills.Column(0, i)
Debug.Print strUpdate
Set db = CurrentDb
db.Execute strUpdate, dbFailonerror
Set db = Nothing

Answer 2

Try this, by explicitly specifying a format
DoCmd.RunSQL "UPDATE Mills SET LastContactDate = #" & _
Format$(SalesCallDate,"yyyy/mm/dd") & "# WHERE MillID = " & _
lstMills.Column(0, i)
UPDATE:
Maybe there is better way to do it, that is independent of any formattings. The idea is to tranfer the date from table to table, without any combo-, list- or text in between. Therefore any conversion from a date type to string and then back to a date field is avoided.
If the tables can be joined (assuming that MillID is the bound field of the listbox):
DoCmd.RunSQL "UPDATE Mills " & _
"INNER JOIN sourceTable ON Mills.MillID = sourceTable.MillID " & _
"SET LastContactDate = sourceTable.SalesCallDate " & _
"WHERE Mills.MillID = " & lstMills
Otherwise
DoCmd.RunSQL "UPDATE Mills SET LastContactDate = " & _
"(SELECT SalesCallDate FROM sourceTable WHERE ID = " & sourceID & ")" _
"WHERE Mills.MillID = " & lstMills