"Automation Error" "Unspecified Error" When Using Excel-VBA and ADODB Objects - sql

Question

I am creating a macro that looks through a folder, performs a SQL operation on each of the documents, and copies the results into another workbook; however, every time I debug and hit the Set rs = cn.Execute(sql) line I get an
"Automation Error" "Unspecified Error" .
The even weirder thing is that when I just run the code, I get an
"Execute of object _Connection failed" error.
I have tested the SQL code in microsoft SQL server already and each of these statements are almost verbatim with code I have previously got to work.
Option Explicit
Sub hardnessTests()
On Error GoTo ErrorHandling
Dim filename As Variant, n As Long
n = 0
Call turnOff
filename = Dir("T:\Marketing\Data Analytics\GIS Data\Water Quality Portal Data\County Summary Results\*")
While filename <> ""
Dim file As String, cn As Object, rs As Object, sql As String, hardField As ADODB.Field
file = "T:\Marketing\Data Analytics\GIS Data\Water Quality Portal Data\County Summary Results\" & filename
Set cn = CreateObject("ADODB.Connection")
With cn
.Provider = "Microsoft.ACE.OLEDB.12.0"
.connectionstring = "Data Source=" & file & ";Extended Properties=""Excel 12.0 Xml;HDR=YES;Readonly=false;IMEX=0"";"
.Open
End With
sql = "SELECT c.STATEFP, c.COUNTYFP, AVG(CAST(a.ResultMeasureValue AS NUMERIC)) AS Average_Surface_Water_Hardness, COUNT(a.ResultMeasureValue) AS Number_Of_Surface_Water_Tests, " & _
"AVG(CAST(b.ResultMeasureValue AS NUMERIC)) AS Average_Groundwater_Hardness, COUNT(b.ResultMeasureValue) AS Number_Of_Groundwater_Tests " & _
"FROM (SELECT * FROM [Sheet1$] WHERE CAST(LEFT(ActivityStartDate, 4) AS NUMERIC) >= 2010 and ActivityMediaSubdivisionName = 'Surface Water') a, " & _
"(SELECT * FROM [Sheet1$] WHERE CAST(LEFT(ActivityStartDate, 4) AS NUMERIC) >= 2010 AND ActivityMediaSubdivisionName = 'Groundwater') b, " & _
"(SELECT * FROM [Sheet1$] WHERE CAST(LEFT(ActivityStartDate, 4) AS NUMERIC) >= 2010 ) c GROUP BY c.STATEFP, c.COUNTYFP ORDER BY c.STATEFP, c.COUNTYFP"
Set rs = cn.Execute(sql)
Dim wb As Workbook, fieldCount As Long
fieldCount = 0
Set wb = Workbooks.Add
wb.SaveAs "T:\Marketing\Data Analytics\GIS Data\Water Quality Portal Data\County Summary Results\ALL_HARDNESS.xlsx"
If n = 0 Then
wb.Worksheets("Sheet1").Range("A2").CopyFromRecordset rs
Else:
wb.Worksheets("Sheet1").Range("A2").End(xlDown).CopyFromRecordset rs
End If
filename = Dir
n = n + 1
Wend
For Each hardField In rs.Fields
wb.Worksheets("Sheet1").Range("A1").Offset(0, fieldCount) = hardField.Name
fieldCount = fieldCount + 1
Next hardField
Call turnOn
Exit Sub
ErrorHandling:
MsgBox ("Source: " & Err.Source & vbNewLine & "Number: " & Err.Number & vbNewLine & "Description: " & Err.Description & vbNewLine & "Help Context: " & Err.HelpContext)
Done:
End Sub
Private Sub turnOff()
Application.Calculation = xlCalculationManual
Application.ScreenUpdating = False
End Sub
Private Sub turnOn()
Application.Calculation = xlCalculationManual
Application.ScreenUpdating = True
End Sub
Thanks for any help!